/**
 * Less - Leaner CSS v3.10.3
 * http://lesscss.org
 * 
 * Copyright (c) 2009-2019, Alexis Sellier <self@cloudhead.net>
 * Licensed under the Apache-2.0 License.
 *
 * @license Apache-2.0
 */

 (function (global, factory) {
    typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
    typeof define === 'function' && define.amd ? define(factory) :
    (global = global || self, global.less = factory());
  }(this, function () { 'use strict';
  
    // Export a new default each time
    var defaultOptions = (function () {
      return {
        /* Inline Javascript - @plugin still allowed */
        javascriptEnabled: false,
  
        /* Outputs a makefile import dependency list to stdout. */
        depends: false,
  
        /* (DEPRECATED) Compress using less built-in compression. 
        * This does an okay job but does not utilise all the tricks of 
        * dedicated css compression. */
        compress: false,
  
        /* Runs the less parser and just reports errors without any output. */
        lint: false,
  
        /* Sets available include paths.
        * If the file in an @import rule does not exist at that exact location, 
        * less will look for it at the location(s) passed to this option. 
        * You might use this for instance to specify a path to a library which 
        * you want to be referenced simply and relatively in the less files. */
        paths: [],
  
        /* color output in the terminal */
        color: true,
  
        /* The strictImports controls whether the compiler will allow an @import inside of either 
        * @media blocks or (a later addition) other selector blocks.
        * See: https://github.com/less/less.js/issues/656 */
        strictImports: false,
  
        /* Allow Imports from Insecure HTTPS Hosts */
        insecure: false,
  
        /* Allows you to add a path to every generated import and url in your css. 
        * This does not affect less import statements that are processed, just ones 
        * that are left in the output css. */
        rootpath: '',
  
        /* By default URLs are kept as-is, so if you import a file in a sub-directory 
        * that references an image, exactly the same URL will be output in the css. 
        * This option allows you to re-write URL's in imported files so that the 
        * URL is always relative to the base imported file */
        rewriteUrls: false,
  
        /* How to process math 
        *   0 always           - eagerly try to solve all operations
        *   1 parens-division  - require parens for division "/"
        *   2 parens | strict  - require parens for all operations
        *   3 strict-legacy    - legacy strict behavior (super-strict)
        */
        math: 0,
  
        /* Without this option, less attempts to guess at the output unit when it does maths. */
        strictUnits: false,
  
        /* Effectively the declaration is put at the top of your base Less file, 
        * meaning it can be used but it also can be overridden if this variable 
        * is defined in the file. */
        globalVars: null,
  
        /* As opposed to the global variable option, this puts the declaration at the
        * end of your base file, meaning it will override anything defined in your Less file. */
        modifyVars: null,
  
        /* This option allows you to specify a argument to go on to every URL.  */
        urlArgs: ''
      };
    });
  
    function extractId(href) {
      return href.replace(/^[a-z-]+:\/+?[^\/]+/, '') // Remove protocol & domain
      .replace(/[\?\&]livereload=\w+/, '') // Remove LiveReload cachebuster
      .replace(/^\//, '') // Remove root /
      .replace(/\.[a-zA-Z]+$/, '') // Remove simple extension
      .replace(/[^\.\w-]+/g, '-') // Replace illegal characters
      .replace(/\./g, ':'); // Replace dots with colons(for valid id)
    }
    function addDataAttr(options, tag) {
      for (var opt in tag.dataset) {
        if (tag.dataset.hasOwnProperty(opt)) {
          if (opt === 'env' || opt === 'dumpLineNumbers' || opt === 'rootpath' || opt === 'errorReporting') {
            options[opt] = tag.dataset[opt];
          } else {
            try {
              options[opt] = JSON.parse(tag.dataset[opt]);
            } catch (_) {}
          }
        }
      }
    }
  
    var browser = {
      createCSS: function createCSS(document, styles, sheet) {
        // Strip the query-string
        var href = sheet.href || ''; // If there is no title set, use the filename, minus the extension
  
        var id = "less:".concat(sheet.title || extractId(href)); // If this has already been inserted into the DOM, we may need to replace it
  
        var oldStyleNode = document.getElementById(id);
        var keepOldStyleNode = false; // Create a new stylesheet node for insertion or (if necessary) replacement
  
        var styleNode = document.createElement('style');
        styleNode.setAttribute('type', 'text/css');
  
        if (sheet.media) {
          styleNode.setAttribute('media', sheet.media);
        }
  
        styleNode.id = id;
  
        if (!styleNode.styleSheet) {
          styleNode.appendChild(document.createTextNode(styles)); // If new contents match contents of oldStyleNode, don't replace oldStyleNode
  
          keepOldStyleNode = oldStyleNode !== null && oldStyleNode.childNodes.length > 0 && styleNode.childNodes.length > 0 && oldStyleNode.firstChild.nodeValue === styleNode.firstChild.nodeValue;
        }
  
        var head = document.getElementsByTagName('head')[0]; // If there is no oldStyleNode, just append; otherwise, only append if we need
        // to replace oldStyleNode with an updated stylesheet
  
        if (oldStyleNode === null || keepOldStyleNode === false) {
          var nextEl = sheet && sheet.nextSibling || null;
  
          if (nextEl) {
            nextEl.parentNode.insertBefore(styleNode, nextEl);
          } else {
            head.appendChild(styleNode);
          }
        }
  
        if (oldStyleNode && keepOldStyleNode === false) {
          oldStyleNode.parentNode.removeChild(oldStyleNode);
        } // For IE.
        // This needs to happen *after* the style element is added to the DOM, otherwise IE 7 and 8 may crash.
        // See http://social.msdn.microsoft.com/Forums/en-US/7e081b65-878a-4c22-8e68-c10d39c2ed32/internet-explorer-crashes-appending-style-element-to-head
  
  
        if (styleNode.styleSheet) {
          try {
            styleNode.styleSheet.cssText = styles;
          } catch (e) {
            throw new Error('Couldn\'t reassign styleSheet.cssText.');
          }
        }
      },
      currentScript: function currentScript(window) {
        var document = window.document;
        return document.currentScript || function () {
          var scripts = document.getElementsByTagName('script');
          return scripts[scripts.length - 1];
        }();
      }
    };
  
    var addDefaultOptions = (function (window, options) {
      // use options from the current script tag data attribues
      addDataAttr(options, browser.currentScript(window));
  
      if (options.isFileProtocol === undefined) {
        options.isFileProtocol = /^(file|(chrome|safari)(-extension)?|resource|qrc|app):/.test(window.location.protocol);
      } // Load styles asynchronously (default: false)
      //
      // This is set to `false` by default, so that the body
      // doesn't start loading before the stylesheets are parsed.
      // Setting this to `true` can result in flickering.
      //
  
  
      options.async = options.async || false;
      options.fileAsync = options.fileAsync || false; // Interval between watch polls
  
      options.poll = options.poll || (options.isFileProtocol ? 1000 : 1500);
      options.env = options.env || (window.location.hostname == '127.0.0.1' || window.location.hostname == '0.0.0.0' || window.location.hostname == 'localhost' || window.location.port && window.location.port.length > 0 || options.isFileProtocol ? 'development' : 'production');
      var dumpLineNumbers = /!dumpLineNumbers:(comments|mediaquery|all)/.exec(window.location.hash);
  
      if (dumpLineNumbers) {
        options.dumpLineNumbers = dumpLineNumbers[1];
      }
  
      if (options.useFileCache === undefined) {
        options.useFileCache = true;
      }
  
      if (options.onReady === undefined) {
        options.onReady = true;
      }
  
      if (options.relativeUrls) {
        options.rewriteUrls = 'all';
      }
    });
  
    function _typeof(obj) {
      if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") {
        _typeof = function (obj) {
          return typeof obj;
        };
      } else {
        _typeof = function (obj) {
          return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj;
        };
      }
  
      return _typeof(obj);
    }
  
    function _classCallCheck(instance, Constructor) {
      if (!(instance instanceof Constructor)) {
        throw new TypeError("Cannot call a class as a function");
      }
    }
  
    function _defineProperties(target, props) {
      for (var i = 0; i < props.length; i++) {
        var descriptor = props[i];
        descriptor.enumerable = descriptor.enumerable || false;
        descriptor.configurable = true;
        if ("value" in descriptor) descriptor.writable = true;
        Object.defineProperty(target, descriptor.key, descriptor);
      }
    }
  
    function _createClass(Constructor, protoProps, staticProps) {
      if (protoProps) _defineProperties(Constructor.prototype, protoProps);
      if (staticProps) _defineProperties(Constructor, staticProps);
      return Constructor;
    }
  
    function _inherits(subClass, superClass) {
      if (typeof superClass !== "function" && superClass !== null) {
        throw new TypeError("Super expression must either be null or a function");
      }
  
      subClass.prototype = Object.create(superClass && superClass.prototype, {
        constructor: {
          value: subClass,
          writable: true,
          configurable: true
        }
      });
      if (superClass) _setPrototypeOf(subClass, superClass);
    }
  
    function _getPrototypeOf(o) {
      _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf : function _getPrototypeOf(o) {
        return o.__proto__ || Object.getPrototypeOf(o);
      };
      return _getPrototypeOf(o);
    }
  
    function _setPrototypeOf(o, p) {
      _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) {
        o.__proto__ = p;
        return o;
      };
  
      return _setPrototypeOf(o, p);
    }
  
    function isNativeReflectConstruct() {
      if (typeof Reflect === "undefined" || !Reflect.construct) return false;
      if (Reflect.construct.sham) return false;
      if (typeof Proxy === "function") return true;
  
      try {
        Date.prototype.toString.call(Reflect.construct(Date, [], function () {}));
        return true;
      } catch (e) {
        return false;
      }
    }
  
    function _construct(Parent, args, Class) {
      if (isNativeReflectConstruct()) {
        _construct = Reflect.construct;
      } else {
        _construct = function _construct(Parent, args, Class) {
          var a = [null];
          a.push.apply(a, args);
          var Constructor = Function.bind.apply(Parent, a);
          var instance = new Constructor();
          if (Class) _setPrototypeOf(instance, Class.prototype);
          return instance;
        };
      }
  
      return _construct.apply(null, arguments);
    }
  
    function _assertThisInitialized(self) {
      if (self === void 0) {
        throw new ReferenceError("this hasn't been initialised - super() hasn't been called");
      }
  
      return self;
    }
  
    function _possibleConstructorReturn(self, call) {
      if (call && (typeof call === "object" || typeof call === "function")) {
        return call;
      }
  
      return _assertThisInitialized(self);
    }
  
    function _toConsumableArray(arr) {
      return _arrayWithoutHoles(arr) || _iterableToArray(arr) || _nonIterableSpread();
    }
  
    function _arrayWithoutHoles(arr) {
      if (Array.isArray(arr)) {
        for (var i = 0, arr2 = new Array(arr.length); i < arr.length; i++) arr2[i] = arr[i];
  
        return arr2;
      }
    }
  
    function _iterableToArray(iter) {
      if (Symbol.iterator in Object(iter) || Object.prototype.toString.call(iter) === "[object Arguments]") return Array.from(iter);
    }
  
    function _nonIterableSpread() {
      throw new TypeError("Invalid attempt to spread non-iterable instance");
    }
  
    var colors = {
      'aliceblue': '#f0f8ff',
      'antiquewhite': '#faebd7',
      'aqua': '#00ffff',
      'aquamarine': '#7fffd4',
      'azure': '#f0ffff',
      'beige': '#f5f5dc',
      'bisque': '#ffe4c4',
      'black': '#000000',
      'blanchedalmond': '#ffebcd',
      'blue': '#0000ff',
      'blueviolet': '#8a2be2',
      'brown': '#a52a2a',
      'burlywood': '#deb887',
      'cadetblue': '#5f9ea0',
      'chartreuse': '#7fff00',
      'chocolate': '#d2691e',
      'coral': '#ff7f50',
      'cornflowerblue': '#6495ed',
      'cornsilk': '#fff8dc',
      'crimson': '#dc143c',
      'cyan': '#00ffff',
      'darkblue': '#00008b',
      'darkcyan': '#008b8b',
      'darkgoldenrod': '#b8860b',
      'darkgray': '#a9a9a9',
      'darkgrey': '#a9a9a9',
      'darkgreen': '#006400',
      'darkkhaki': '#bdb76b',
      'darkmagenta': '#8b008b',
      'darkolivegreen': '#556b2f',
      'darkorange': '#ff8c00',
      'darkorchid': '#9932cc',
      'darkred': '#8b0000',
      'darksalmon': '#e9967a',
      'darkseagreen': '#8fbc8f',
      'darkslateblue': '#483d8b',
      'darkslategray': '#2f4f4f',
      'darkslategrey': '#2f4f4f',
      'darkturquoise': '#00ced1',
      'darkviolet': '#9400d3',
      'deeppink': '#ff1493',
      'deepskyblue': '#00bfff',
      'dimgray': '#696969',
      'dimgrey': '#696969',
      'dodgerblue': '#1e90ff',
      'firebrick': '#b22222',
      'floralwhite': '#fffaf0',
      'forestgreen': '#228b22',
      'fuchsia': '#ff00ff',
      'gainsboro': '#dcdcdc',
      'ghostwhite': '#f8f8ff',
      'gold': '#ffd700',
      'goldenrod': '#daa520',
      'gray': '#808080',
      'grey': '#808080',
      'green': '#008000',
      'greenyellow': '#adff2f',
      'honeydew': '#f0fff0',
      'hotpink': '#ff69b4',
      'indianred': '#cd5c5c',
      'indigo': '#4b0082',
      'ivory': '#fffff0',
      'khaki': '#f0e68c',
      'lavender': '#e6e6fa',
      'lavenderblush': '#fff0f5',
      'lawngreen': '#7cfc00',
      'lemonchiffon': '#fffacd',
      'lightblue': '#add8e6',
      'lightcoral': '#f08080',
      'lightcyan': '#e0ffff',
      'lightgoldenrodyellow': '#fafad2',
      'lightgray': '#d3d3d3',
      'lightgrey': '#d3d3d3',
      'lightgreen': '#90ee90',
      'lightpink': '#ffb6c1',
      'lightsalmon': '#ffa07a',
      'lightseagreen': '#20b2aa',
      'lightskyblue': '#87cefa',
      'lightslategray': '#778899',
      'lightslategrey': '#778899',
      'lightsteelblue': '#b0c4de',
      'lightyellow': '#ffffe0',
      'lime': '#00ff00',
      'limegreen': '#32cd32',
      'linen': '#faf0e6',
      'magenta': '#ff00ff',
      'maroon': '#800000',
      'mediumaquamarine': '#66cdaa',
      'mediumblue': '#0000cd',
      'mediumorchid': '#ba55d3',
      'mediumpurple': '#9370d8',
      'mediumseagreen': '#3cb371',
      'mediumslateblue': '#7b68ee',
      'mediumspringgreen': '#00fa9a',
      'mediumturquoise': '#48d1cc',
      'mediumvioletred': '#c71585',
      'midnightblue': '#191970',
      'mintcream': '#f5fffa',
      'mistyrose': '#ffe4e1',
      'moccasin': '#ffe4b5',
      'navajowhite': '#ffdead',
      'navy': '#000080',
      'oldlace': '#fdf5e6',
      'olive': '#808000',
      'olivedrab': '#6b8e23',
      'orange': '#ffa500',
      'orangered': '#ff4500',
      'orchid': '#da70d6',
      'palegoldenrod': '#eee8aa',
      'palegreen': '#98fb98',
      'paleturquoise': '#afeeee',
      'palevioletred': '#d87093',
      'papayawhip': '#ffefd5',
      'peachpuff': '#ffdab9',
      'peru': '#cd853f',
      'pink': '#ffc0cb',
      'plum': '#dda0dd',
      'powderblue': '#b0e0e6',
      'purple': '#800080',
      'rebeccapurple': '#663399',
      'red': '#ff0000',
      'rosybrown': '#bc8f8f',
      'royalblue': '#4169e1',
      'saddlebrown': '#8b4513',
      'salmon': '#fa8072',
      'sandybrown': '#f4a460',
      'seagreen': '#2e8b57',
      'seashell': '#fff5ee',
      'sienna': '#a0522d',
      'silver': '#c0c0c0',
      'skyblue': '#87ceeb',
      'slateblue': '#6a5acd',
      'slategray': '#708090',
      'slategrey': '#708090',
      'snow': '#fffafa',
      'springgreen': '#00ff7f',
      'steelblue': '#4682b4',
      'tan': '#d2b48c',
      'teal': '#008080',
      'thistle': '#d8bfd8',
      'tomato': '#ff6347',
      'turquoise': '#40e0d0',
      'violet': '#ee82ee',
      'wheat': '#f5deb3',
      'white': '#ffffff',
      'whitesmoke': '#f5f5f5',
      'yellow': '#ffff00',
      'yellowgreen': '#9acd32'
    };
  
    var unitConversions = {
      length: {
        'm': 1,
        'cm': 0.01,
        'mm': 0.001,
        'in': 0.0254,
        'px': 0.0254 / 96,
        'pt': 0.0254 / 72,
        'pc': 0.0254 / 72 * 12
      },
      duration: {
        's': 1,
        'ms': 0.001
      },
      angle: {
        'rad': 1 / (2 * Math.PI),
        'deg': 1 / 360,
        'grad': 1 / 400,
        'turn': 1
      }
    };
  
    var data = {
      colors: colors,
      unitConversions: unitConversions
    };
  
    var Node =
    /*#__PURE__*/
    function () {
      function Node() {
        _classCallCheck(this, Node);
  
        this.parent = null;
        this.visibilityBlocks = undefined;
        this.nodeVisible = undefined;
        this.rootNode = null;
        this.parsed = null;
        var self = this;
        Object.defineProperty(this, 'currentFileInfo', {
          get: function get() {
            return self.fileInfo();
          }
        });
        Object.defineProperty(this, 'index', {
          get: function get() {
            return self.getIndex();
          }
        });
      }
  
      _createClass(Node, [{
        key: "setParent",
        value: function setParent(nodes, parent) {
          function set(node) {
            if (node && node instanceof Node) {
              node.parent = parent;
            }
          }
  
          if (Array.isArray(nodes)) {
            nodes.forEach(set);
          } else {
            set(nodes);
          }
        }
      }, {
        key: "getIndex",
        value: function getIndex() {
          return this._index || this.parent && this.parent.getIndex() || 0;
        }
      }, {
        key: "fileInfo",
        value: function fileInfo() {
          return this._fileInfo || this.parent && this.parent.fileInfo() || {};
        }
      }, {
        key: "isRulesetLike",
        value: function isRulesetLike() {
          return false;
        }
      }, {
        key: "toCSS",
        value: function toCSS(context) {
          var strs = [];
          this.genCSS(context, {
            add: function add(chunk, fileInfo, index) {
              strs.push(chunk);
            },
            isEmpty: function isEmpty() {
              return strs.length === 0;
            }
          });
          return strs.join('');
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add(this.value);
        }
      }, {
        key: "accept",
        value: function accept(visitor) {
          this.value = visitor.visit(this.value);
        }
      }, {
        key: "eval",
        value: function _eval() {
          return this;
        }
      }, {
        key: "_operate",
        value: function _operate(context, op, a, b) {
          switch (op) {
            case '+':
              return a + b;
  
            case '-':
              return a - b;
  
            case '*':
              return a * b;
  
            case '/':
              return a / b;
          }
        }
      }, {
        key: "fround",
        value: function fround(context, value) {
          var precision = context && context.numPrecision; // add "epsilon" to ensure numbers like 1.000000005 (represented as 1.000000004999...) are properly rounded:
  
          return precision ? Number((value + 2e-16).toFixed(precision)) : value;
        } // Returns true if this node represents root of ast imported by reference
  
      }, {
        key: "blocksVisibility",
        value: function blocksVisibility() {
          if (this.visibilityBlocks == null) {
            this.visibilityBlocks = 0;
          }
  
          return this.visibilityBlocks !== 0;
        }
      }, {
        key: "addVisibilityBlock",
        value: function addVisibilityBlock() {
          if (this.visibilityBlocks == null) {
            this.visibilityBlocks = 0;
          }
  
          this.visibilityBlocks = this.visibilityBlocks + 1;
        }
      }, {
        key: "removeVisibilityBlock",
        value: function removeVisibilityBlock() {
          if (this.visibilityBlocks == null) {
            this.visibilityBlocks = 0;
          }
  
          this.visibilityBlocks = this.visibilityBlocks - 1;
        } // Turns on node visibility - if called node will be shown in output regardless
        // of whether it comes from import by reference or not
  
      }, {
        key: "ensureVisibility",
        value: function ensureVisibility() {
          this.nodeVisible = true;
        } // Turns off node visibility - if called node will NOT be shown in output regardless
        // of whether it comes from import by reference or not
  
      }, {
        key: "ensureInvisibility",
        value: function ensureInvisibility() {
          this.nodeVisible = false;
        } // return values:
        // false - the node must not be visible
        // true - the node must be visible
        // undefined or null - the node has the same visibility as its parent
  
      }, {
        key: "isVisible",
        value: function isVisible() {
          return this.nodeVisible;
        }
      }, {
        key: "visibilityInfo",
        value: function visibilityInfo() {
          return {
            visibilityBlocks: this.visibilityBlocks,
            nodeVisible: this.nodeVisible
          };
        }
      }, {
        key: "copyVisibilityInfo",
        value: function copyVisibilityInfo(info) {
          if (!info) {
            return;
          }
  
          this.visibilityBlocks = info.visibilityBlocks;
          this.nodeVisible = info.nodeVisible;
        }
      }]);
  
      return Node;
    }();
  
    Node.compare = function (a, b) {
      /* returns:
       -1: a < b
       0: a = b
       1: a > b
       and *any* other value for a != b (e.g. undefined, NaN, -2 etc.) */
      if (a.compare && // for "symmetric results" force toCSS-based comparison
      // of Quoted or Anonymous if either value is one of those
      !(b.type === 'Quoted' || b.type === 'Anonymous')) {
        return a.compare(b);
      } else if (b.compare) {
        return -b.compare(a);
      } else if (a.type !== b.type) {
        return undefined;
      }
  
      a = a.value;
      b = b.value;
  
      if (!Array.isArray(a)) {
        return a === b ? 0 : undefined;
      }
  
      if (a.length !== b.length) {
        return undefined;
      }
  
      for (var i = 0; i < a.length; i++) {
        if (Node.compare(a[i], b[i]) !== 0) {
          return undefined;
        }
      }
  
      return 0;
    };
  
    Node.numericCompare = function (a, b) {
      return a < b ? -1 : a === b ? 0 : a > b ? 1 : undefined;
    };
  
    // RGB Colors - #ff0014, #eee
    //
  
    var Color =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Color, _Node);
  
      function Color(rgb, a, originalForm) {
        var _this;
  
        _classCallCheck(this, Color);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Color).call(this));
  
        var self = _assertThisInitialized(_this); //
        // The end goal here, is to parse the arguments
        // into an integer triplet, such as `128, 255, 0`
        //
        // This facilitates operations and conversions.
        //
  
  
        if (Array.isArray(rgb)) {
          _this.rgb = rgb;
        } else if (rgb.length >= 6) {
          _this.rgb = [];
          rgb.match(/.{2}/g).map(function (c, i) {
            if (i < 3) {
              self.rgb.push(parseInt(c, 16));
            } else {
              self.alpha = parseInt(c, 16) / 255;
            }
          });
        } else {
          _this.rgb = [];
          rgb.split('').map(function (c, i) {
            if (i < 3) {
              self.rgb.push(parseInt(c + c, 16));
            } else {
              self.alpha = parseInt(c + c, 16) / 255;
            }
          });
        }
  
        _this.alpha = _this.alpha || (typeof a === 'number' ? a : 1);
  
        if (typeof originalForm !== 'undefined') {
          _this.value = originalForm;
        }
  
        return _this;
      }
  
      _createClass(Color, [{
        key: "luma",
        value: function luma() {
          var r = this.rgb[0] / 255;
          var g = this.rgb[1] / 255;
          var b = this.rgb[2] / 255;
          r = r <= 0.03928 ? r / 12.92 : Math.pow((r + 0.055) / 1.055, 2.4);
          g = g <= 0.03928 ? g / 12.92 : Math.pow((g + 0.055) / 1.055, 2.4);
          b = b <= 0.03928 ? b / 12.92 : Math.pow((b + 0.055) / 1.055, 2.4);
          return 0.2126 * r + 0.7152 * g + 0.0722 * b;
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add(this.toCSS(context));
        }
      }, {
        key: "toCSS",
        value: function toCSS(context, doNotCompress) {
          var compress = context && context.compress && !doNotCompress;
          var color;
          var alpha;
          var colorFunction;
          var args = []; // `value` is set if this color was originally
          // converted from a named color string so we need
          // to respect this and try to output named color too.
  
          alpha = this.fround(context, this.alpha);
  
          if (this.value) {
            if (this.value.indexOf('rgb') === 0) {
              if (alpha < 1) {
                colorFunction = 'rgba';
              }
            } else if (this.value.indexOf('hsl') === 0) {
              if (alpha < 1) {
                colorFunction = 'hsla';
              } else {
                colorFunction = 'hsl';
              }
            } else {
              return this.value;
            }
          } else {
            if (alpha < 1) {
              colorFunction = 'rgba';
            }
          }
  
          switch (colorFunction) {
            case 'rgba':
              args = this.rgb.map(function (c) {
                return clamp(Math.round(c), 255);
              }).concat(clamp(alpha, 1));
              break;
  
            case 'hsla':
              args.push(clamp(alpha, 1));
  
            case 'hsl':
              color = this.toHSL();
              args = [this.fround(context, color.h), "".concat(this.fround(context, color.s * 100), "%"), "".concat(this.fround(context, color.l * 100), "%")].concat(args);
          }
  
          if (colorFunction) {
            // Values are capped between `0` and `255`, rounded and zero-padded.
            return "".concat(colorFunction, "(").concat(args.join(",".concat(compress ? '' : ' ')), ")");
          }
  
          color = this.toRGB();
  
          if (compress) {
            var splitcolor = color.split(''); // Convert color to short format
  
            if (splitcolor[1] === splitcolor[2] && splitcolor[3] === splitcolor[4] && splitcolor[5] === splitcolor[6]) {
              color = "#".concat(splitcolor[1]).concat(splitcolor[3]).concat(splitcolor[5]);
            }
          }
  
          return color;
        } //
        // Operations have to be done per-channel, if not,
        // channels will spill onto each other. Once we have
        // our result, in the form of an integer triplet,
        // we create a new Color node to hold the result.
        //
  
      }, {
        key: "operate",
        value: function operate(context, op, other) {
          var rgb = new Array(3);
          var alpha = this.alpha * (1 - other.alpha) + other.alpha;
  
          for (var c = 0; c < 3; c++) {
            rgb[c] = this._operate(context, op, this.rgb[c], other.rgb[c]);
          }
  
          return new Color(rgb, alpha);
        }
      }, {
        key: "toRGB",
        value: function toRGB() {
          return toHex(this.rgb);
        }
      }, {
        key: "toHSL",
        value: function toHSL() {
          var r = this.rgb[0] / 255;
          var g = this.rgb[1] / 255;
          var b = this.rgb[2] / 255;
          var a = this.alpha;
          var max = Math.max(r, g, b);
          var min = Math.min(r, g, b);
          var h;
          var s;
          var l = (max + min) / 2;
          var d = max - min;
  
          if (max === min) {
            h = s = 0;
          } else {
            s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
  
            switch (max) {
              case r:
                h = (g - b) / d + (g < b ? 6 : 0);
                break;
  
              case g:
                h = (b - r) / d + 2;
                break;
  
              case b:
                h = (r - g) / d + 4;
                break;
            }
  
            h /= 6;
          }
  
          return {
            h: h * 360,
            s: s,
            l: l,
            a: a
          };
        } // Adapted from http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
  
      }, {
        key: "toHSV",
        value: function toHSV() {
          var r = this.rgb[0] / 255;
          var g = this.rgb[1] / 255;
          var b = this.rgb[2] / 255;
          var a = this.alpha;
          var max = Math.max(r, g, b);
          var min = Math.min(r, g, b);
          var h;
          var s;
          var v = max;
          var d = max - min;
  
          if (max === 0) {
            s = 0;
          } else {
            s = d / max;
          }
  
          if (max === min) {
            h = 0;
          } else {
            switch (max) {
              case r:
                h = (g - b) / d + (g < b ? 6 : 0);
                break;
  
              case g:
                h = (b - r) / d + 2;
                break;
  
              case b:
                h = (r - g) / d + 4;
                break;
            }
  
            h /= 6;
          }
  
          return {
            h: h * 360,
            s: s,
            v: v,
            a: a
          };
        }
      }, {
        key: "toARGB",
        value: function toARGB() {
          return toHex([this.alpha * 255].concat(this.rgb));
        }
      }, {
        key: "compare",
        value: function compare(x) {
          return x.rgb && x.rgb[0] === this.rgb[0] && x.rgb[1] === this.rgb[1] && x.rgb[2] === this.rgb[2] && x.alpha === this.alpha ? 0 : undefined;
        }
      }]);
  
      return Color;
    }(Node);
  
    Color.prototype.type = 'Color';
  
    function clamp(v, max) {
      return Math.min(Math.max(v, 0), max);
    }
  
    function toHex(v) {
      return "#".concat(v.map(function (c) {
        c = clamp(Math.round(c), 255);
        return (c < 16 ? '0' : '') + c.toString(16);
      }).join(''));
    }
  
    Color.fromKeyword = function (keyword) {
      var c;
      var key = keyword.toLowerCase();
  
      if (colors.hasOwnProperty(key)) {
        c = new Color(colors[key].slice(1));
      } else if (key === 'transparent') {
        c = new Color([0, 0, 0], 0);
      }
  
      if (c) {
        c.value = keyword;
        return c;
      }
    };
  
    var Paren =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Paren, _Node);
  
      function Paren(node) {
        var _this;
  
        _classCallCheck(this, Paren);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Paren).call(this));
        _this.value = node;
        return _this;
      }
  
      _createClass(Paren, [{
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add('(');
          this.value.genCSS(context, output);
          output.add(')');
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          return new Paren(this.value.eval(context));
        }
      }]);
  
      return Paren;
    }(Node);
  
    Paren.prototype.type = 'Paren';
  
    var _noSpaceCombinators = {
      '': true,
      ' ': true,
      '|': true
    };
  
    var Combinator =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Combinator, _Node);
  
      function Combinator(value) {
        var _this;
  
        _classCallCheck(this, Combinator);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Combinator).call(this));
  
        if (value === ' ') {
          _this.value = ' ';
          _this.emptyOrWhitespace = true;
        } else {
          _this.value = value ? value.trim() : '';
          _this.emptyOrWhitespace = _this.value === '';
        }
  
        return _this;
      }
  
      _createClass(Combinator, [{
        key: "genCSS",
        value: function genCSS(context, output) {
          var spaceOrEmpty = context.compress || _noSpaceCombinators[this.value] ? '' : ' ';
          output.add(spaceOrEmpty + this.value + spaceOrEmpty);
        }
      }]);
  
      return Combinator;
    }(Node);
  
    Combinator.prototype.type = 'Combinator';
  
    var Element =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Element, _Node);
  
      function Element(combinator, value, isVariable, index, currentFileInfo, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, Element);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Element).call(this));
        _this.combinator = combinator instanceof Combinator ? combinator : new Combinator(combinator);
  
        if (typeof value === 'string') {
          _this.value = value.trim();
        } else if (value) {
          _this.value = value;
        } else {
          _this.value = '';
        }
  
        _this.isVariable = isVariable;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        _this.setParent(_this.combinator, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(Element, [{
        key: "accept",
        value: function accept(visitor) {
          var value = this.value;
          this.combinator = visitor.visit(this.combinator);
  
          if (_typeof(value) === 'object') {
            this.value = visitor.visit(value);
          }
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          return new Element(this.combinator, this.value.eval ? this.value.eval(context) : this.value, this.isVariable, this.getIndex(), this.fileInfo(), this.visibilityInfo());
        }
      }, {
        key: "clone",
        value: function clone() {
          return new Element(this.combinator, this.value, this.isVariable, this.getIndex(), this.fileInfo(), this.visibilityInfo());
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add(this.toCSS(context), this.fileInfo(), this.getIndex());
        }
      }, {
        key: "toCSS",
        value: function toCSS() {
          var context = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
          var value = this.value;
          var firstSelector = context.firstSelector;
  
          if (value instanceof Paren) {
            // selector in parens should not be affected by outer selector
            // flags (breaks only interpolated selectors - see #1973)
            context.firstSelector = true;
          }
  
          value = value.toCSS ? value.toCSS(context) : value;
          context.firstSelector = firstSelector;
  
          if (value === '' && this.combinator.value.charAt(0) === '&') {
            return '';
          } else {
            return this.combinator.toCSS(context) + value;
          }
        }
      }]);
  
      return Element;
    }(Node);
  
    Element.prototype.type = 'Element';
  
    var Math$1 = {
      ALWAYS: 0,
      PARENS_DIVISION: 1,
      PARENS: 2,
      STRICT_LEGACY: 3
    };
    var RewriteUrls = {
      OFF: 0,
      LOCAL: 1,
      ALL: 2
    };
  
    function createCommonjsModule(fn, module) {
        return module = { exports: {} }, fn(module, module.exports), module.exports;
    }
  
    var clone_1 = createCommonjsModule(function (module) {
    var clone = (function() {
  
    function _instanceof(obj, type) {
      return type != null && obj instanceof type;
    }
  
    var nativeMap;
    try {
      nativeMap = Map;
    } catch(_) {
      // maybe a reference error because no `Map`. Give it a dummy value that no
      // value will ever be an instanceof.
      nativeMap = function() {};
    }
  
    var nativeSet;
    try {
      nativeSet = Set;
    } catch(_) {
      nativeSet = function() {};
    }
  
    var nativePromise;
    try {
      nativePromise = Promise;
    } catch(_) {
      nativePromise = function() {};
    }
  
    /**
     * Clones (copies) an Object using deep copying.
     *
     * This function supports circular references by default, but if you are certain
     * there are no circular references in your object, you can save some CPU time
     * by calling clone(obj, false).
     *
     * Caution: if `circular` is false and `parent` contains circular references,
     * your program may enter an infinite loop and crash.
     *
     * @param `parent` - the object to be cloned
     * @param `circular` - set to true if the object to be cloned may contain
     *    circular references. (optional - true by default)
     * @param `depth` - set to a number if the object is only to be cloned to
     *    a particular depth. (optional - defaults to Infinity)
     * @param `prototype` - sets the prototype to be used when cloning an object.
     *    (optional - defaults to parent prototype).
     * @param `includeNonEnumerable` - set to true if the non-enumerable properties
     *    should be cloned as well. Non-enumerable properties on the prototype
     *    chain will be ignored. (optional - false by default)
    */
    function clone(parent, circular, depth, prototype, includeNonEnumerable) {
      if (typeof circular === 'object') {
        depth = circular.depth;
        prototype = circular.prototype;
        includeNonEnumerable = circular.includeNonEnumerable;
        circular = circular.circular;
      }
      // maintain two arrays for circular references, where corresponding parents
      // and children have the same index
      var allParents = [];
      var allChildren = [];
  
      var useBuffer = typeof Buffer != 'undefined';
  
      if (typeof circular == 'undefined')
        circular = true;
  
      if (typeof depth == 'undefined')
        depth = Infinity;
  
      // recurse this function so we don't reset allParents and allChildren
      function _clone(parent, depth) {
        // cloning null always returns null
        if (parent === null)
          return null;
  
        if (depth === 0)
          return parent;
  
        var child;
        var proto;
        if (typeof parent != 'object') {
          return parent;
        }
  
        if (_instanceof(parent, nativeMap)) {
          child = new nativeMap();
        } else if (_instanceof(parent, nativeSet)) {
          child = new nativeSet();
        } else if (_instanceof(parent, nativePromise)) {
          child = new nativePromise(function (resolve, reject) {
            parent.then(function(value) {
              resolve(_clone(value, depth - 1));
            }, function(err) {
              reject(_clone(err, depth - 1));
            });
          });
        } else if (clone.__isArray(parent)) {
          child = [];
        } else if (clone.__isRegExp(parent)) {
          child = new RegExp(parent.source, __getRegExpFlags(parent));
          if (parent.lastIndex) child.lastIndex = parent.lastIndex;
        } else if (clone.__isDate(parent)) {
          child = new Date(parent.getTime());
        } else if (useBuffer && Buffer.isBuffer(parent)) {
          if (Buffer.allocUnsafe) {
            // Node.js >= 4.5.0
            child = Buffer.allocUnsafe(parent.length);
          } else {
            // Older Node.js versions
            child = new Buffer(parent.length);
          }
          parent.copy(child);
          return child;
        } else if (_instanceof(parent, Error)) {
          child = Object.create(parent);
        } else {
          if (typeof prototype == 'undefined') {
            proto = Object.getPrototypeOf(parent);
            child = Object.create(proto);
          }
          else {
            child = Object.create(prototype);
            proto = prototype;
          }
        }
  
        if (circular) {
          var index = allParents.indexOf(parent);
  
          if (index != -1) {
            return allChildren[index];
          }
          allParents.push(parent);
          allChildren.push(child);
        }
  
        if (_instanceof(parent, nativeMap)) {
          parent.forEach(function(value, key) {
            var keyChild = _clone(key, depth - 1);
            var valueChild = _clone(value, depth - 1);
            child.set(keyChild, valueChild);
          });
        }
        if (_instanceof(parent, nativeSet)) {
          parent.forEach(function(value) {
            var entryChild = _clone(value, depth - 1);
            child.add(entryChild);
          });
        }
  
        for (var i in parent) {
          var attrs;
          if (proto) {
            attrs = Object.getOwnPropertyDescriptor(proto, i);
          }
  
          if (attrs && attrs.set == null) {
            continue;
          }
          child[i] = _clone(parent[i], depth - 1);
        }
  
        if (Object.getOwnPropertySymbols) {
          var symbols = Object.getOwnPropertySymbols(parent);
          for (var i = 0; i < symbols.length; i++) {
            // Don't need to worry about cloning a symbol because it is a primitive,
            // like a number or string.
            var symbol = symbols[i];
            var descriptor = Object.getOwnPropertyDescriptor(parent, symbol);
            if (descriptor && !descriptor.enumerable && !includeNonEnumerable) {
              continue;
            }
            child[symbol] = _clone(parent[symbol], depth - 1);
            if (!descriptor.enumerable) {
              Object.defineProperty(child, symbol, {
                enumerable: false
              });
            }
          }
        }
  
        if (includeNonEnumerable) {
          var allPropertyNames = Object.getOwnPropertyNames(parent);
          for (var i = 0; i < allPropertyNames.length; i++) {
            var propertyName = allPropertyNames[i];
            var descriptor = Object.getOwnPropertyDescriptor(parent, propertyName);
            if (descriptor && descriptor.enumerable) {
              continue;
            }
            child[propertyName] = _clone(parent[propertyName], depth - 1);
            Object.defineProperty(child, propertyName, {
              enumerable: false
            });
          }
        }
  
        return child;
      }
  
      return _clone(parent, depth);
    }
  
    /**
     * Simple flat clone using prototype, accepts only objects, usefull for property
     * override on FLAT configuration object (no nested props).
     *
     * USE WITH CAUTION! This may not behave as you wish if you do not know how this
     * works.
     */
    clone.clonePrototype = function clonePrototype(parent) {
      if (parent === null)
        return null;
  
      var c = function () {};
      c.prototype = parent;
      return new c();
    };
  
    // private utility functions
  
    function __objToStr(o) {
      return Object.prototype.toString.call(o);
    }
    clone.__objToStr = __objToStr;
  
    function __isDate(o) {
      return typeof o === 'object' && __objToStr(o) === '[object Date]';
    }
    clone.__isDate = __isDate;
  
    function __isArray(o) {
      return typeof o === 'object' && __objToStr(o) === '[object Array]';
    }
    clone.__isArray = __isArray;
  
    function __isRegExp(o) {
      return typeof o === 'object' && __objToStr(o) === '[object RegExp]';
    }
    clone.__isRegExp = __isRegExp;
  
    function __getRegExpFlags(re) {
      var flags = '';
      if (re.global) flags += 'g';
      if (re.ignoreCase) flags += 'i';
      if (re.multiline) flags += 'm';
      return flags;
    }
    clone.__getRegExpFlags = __getRegExpFlags;
  
    return clone;
    })();
  
    if ( module.exports) {
      module.exports = clone;
    }
    });
  
    /* jshint proto: true */
    function getLocation(index, inputStream) {
      var n = index + 1;
      var line = null;
      var column = -1;
  
      while (--n >= 0 && inputStream.charAt(n) !== '\n') {
        column++;
      }
  
      if (typeof index === 'number') {
        line = (inputStream.slice(0, index).match(/\n/g) || '').length;
      }
  
      return {
        line: line,
        column: column
      };
    }
    function copyArray(arr) {
      var i;
      var length = arr.length;
      var copy = new Array(length);
  
      for (i = 0; i < length; i++) {
        copy[i] = arr[i];
      }
  
      return copy;
    }
    function clone(obj) {
      var cloned = {};
  
      for (var prop in obj) {
        if (obj.hasOwnProperty(prop)) {
          cloned[prop] = obj[prop];
        }
      }
  
      return cloned;
    }
    function defaults(obj1, obj2) {
      var newObj = obj2 || {};
  
      if (!obj2._defaults) {
        newObj = {};
  
        var _defaults = clone_1(obj1);
  
        newObj._defaults = _defaults;
        var cloned = obj2 ? clone_1(obj2) : {};
        Object.assign(newObj, _defaults, cloned);
      }
  
      return newObj;
    }
    function copyOptions(obj1, obj2) {
      if (obj2 && obj2._defaults) {
        return obj2;
      }
  
      var opts = defaults(obj1, obj2);
  
      if (opts.strictMath) {
        opts.math = Math$1.STRICT_LEGACY;
      } // Back compat with changed relativeUrls option
  
  
      if (opts.relativeUrls) {
        opts.rewriteUrls = RewriteUrls.ALL;
      }
  
      if (typeof opts.math === 'string') {
        switch (opts.math.toLowerCase()) {
          case 'always':
            opts.math = Math$1.ALWAYS;
            break;
  
          case 'parens-division':
            opts.math = Math$1.PARENS_DIVISION;
            break;
  
          case 'strict':
          case 'parens':
            opts.math = Math$1.PARENS;
            break;
  
          case 'strict-legacy':
            opts.math = Math$1.STRICT_LEGACY;
        }
      }
  
      if (typeof opts.rewriteUrls === 'string') {
        switch (opts.rewriteUrls.toLowerCase()) {
          case 'off':
            opts.rewriteUrls = RewriteUrls.OFF;
            break;
  
          case 'local':
            opts.rewriteUrls = RewriteUrls.LOCAL;
            break;
  
          case 'all':
            opts.rewriteUrls = RewriteUrls.ALL;
            break;
        }
      }
  
      return opts;
    }
    function merge(obj1, obj2) {
      for (var prop in obj2) {
        if (obj2.hasOwnProperty(prop)) {
          obj1[prop] = obj2[prop];
        }
      }
  
      return obj1;
    }
    function flattenArray(arr) {
      var result = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : [];
  
      for (var i = 0, length = arr.length; i < length; i++) {
        var value = arr[i];
  
        if (Array.isArray(value)) {
          flattenArray(value, result);
        } else {
          if (value !== undefined) {
            result.push(value);
          }
        }
      }
  
      return result;
    }
  
    var utils = /*#__PURE__*/Object.freeze({
      getLocation: getLocation,
      copyArray: copyArray,
      clone: clone,
      defaults: defaults,
      copyOptions: copyOptions,
      merge: merge,
      flattenArray: flattenArray
    });
  
    /**
     * This is a centralized class of any error that could be thrown internally (mostly by the parser).
     * Besides standard .message it keeps some additional data like a path to the file where the error
     * occurred along with line and column numbers.
     *
     * @class
     * @extends Error
     * @type {module.LessError}
     *
     * @prop {string} type
     * @prop {string} filename
     * @prop {number} index
     * @prop {number} line
     * @prop {number} column
     * @prop {number} callLine
     * @prop {number} callExtract
     * @prop {string[]} extract
     *
     * @param {Object} e              - An error object to wrap around or just a descriptive object
     * @param {Object} fileContentMap - An object with file contents in 'contents' property (like importManager) @todo - move to fileManager?
     * @param {string} [currentFilename]
     */
  
    var LessError = function LessError(e, fileContentMap, currentFilename) {
      Error.call(this);
      var filename = e.filename || currentFilename;
      this.message = e.message;
      this.stack = e.stack;
  
      if (fileContentMap && filename) {
        var input = fileContentMap.contents[filename];
        var loc = getLocation(e.index, input);
        var line = loc.line;
        var col = loc.column;
        var callLine = e.call && getLocation(e.call, input).line;
        var lines = input ? input.split('\n') : '';
        this.type = e.type || 'Syntax';
        this.filename = filename;
        this.index = e.index;
        this.line = typeof line === 'number' ? line + 1 : null;
        this.column = col;
  
        if (!this.line && this.stack) {
          var found = this.stack.match(/(<anonymous>|Function):(\d+):(\d+)/);
  
          if (found) {
            if (found[2]) {
              this.line = parseInt(found[2]) - 2;
            }
  
            if (found[3]) {
              this.column = parseInt(found[3]);
            }
          }
        }
  
        this.callLine = callLine + 1;
        this.callExtract = lines[callLine];
        this.extract = [lines[this.line - 2], lines[this.line - 1], lines[this.line]];
      }
    };
  
    if (typeof Object.create === 'undefined') {
      var F = function F() {};
  
      F.prototype = Error.prototype;
      LessError.prototype = new F();
    } else {
      LessError.prototype = Object.create(Error.prototype);
    }
  
    LessError.prototype.constructor = LessError;
    /**
     * An overridden version of the default Object.prototype.toString
     * which uses additional information to create a helpful message.
     *
     * @param {Object} options
     * @returns {string}
     */
  
    LessError.prototype.toString = function () {
      var options = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
      var message = '';
      var extract = this.extract || [];
      var error = [];
  
      var stylize = function stylize(str) {
        return str;
      };
  
      if (options.stylize) {
        var type = _typeof(options.stylize);
  
        if (type !== 'function') {
          throw Error("options.stylize should be a function, got a ".concat(type, "!"));
        }
  
        stylize = options.stylize;
      }
  
      if (this.line !== null) {
        if (typeof extract[0] === 'string') {
          error.push(stylize("".concat(this.line - 1, " ").concat(extract[0]), 'grey'));
        }
  
        if (typeof extract[1] === 'string') {
          var errorTxt = "".concat(this.line, " ");
  
          if (extract[1]) {
            errorTxt += extract[1].slice(0, this.column) + stylize(stylize(stylize(extract[1].substr(this.column, 1), 'bold') + extract[1].slice(this.column + 1), 'red'), 'inverse');
          }
  
          error.push(errorTxt);
        }
  
        if (typeof extract[2] === 'string') {
          error.push(stylize("".concat(this.line + 1, " ").concat(extract[2]), 'grey'));
        }
  
        error = "".concat(error.join('\n') + stylize('', 'reset'), "\n");
      }
  
      message += stylize("".concat(this.type, "Error: ").concat(this.message), 'red');
  
      if (this.filename) {
        message += stylize(' in ', 'red') + this.filename;
      }
  
      if (this.line) {
        message += stylize(" on line ".concat(this.line, ", column ").concat(this.column + 1, ":"), 'grey');
      }
  
      message += "\n".concat(error);
  
      if (this.callLine) {
        message += "".concat(stylize('from ', 'red') + (this.filename || ''), "/n");
        message += "".concat(stylize(this.callLine, 'grey'), " ").concat(this.callExtract, "/n");
      }
  
      return message;
    };
  
    var Selector =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Selector, _Node);
  
      function Selector(elements, extendList, condition, index, currentFileInfo, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, Selector);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Selector).call(this));
        _this.extendList = extendList;
        _this.condition = condition;
        _this.evaldCondition = !condition;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.elements = _this.getElements(elements);
        _this.mixinElements_ = undefined;
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        _this.setParent(_this.elements, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(Selector, [{
        key: "accept",
        value: function accept(visitor) {
          if (this.elements) {
            this.elements = visitor.visitArray(this.elements);
          }
  
          if (this.extendList) {
            this.extendList = visitor.visitArray(this.extendList);
          }
  
          if (this.condition) {
            this.condition = visitor.visit(this.condition);
          }
        }
      }, {
        key: "createDerived",
        value: function createDerived(elements, extendList, evaldCondition) {
          elements = this.getElements(elements);
          var newSelector = new Selector(elements, extendList || this.extendList, null, this.getIndex(), this.fileInfo(), this.visibilityInfo());
          newSelector.evaldCondition = evaldCondition != null ? evaldCondition : this.evaldCondition;
          newSelector.mediaEmpty = this.mediaEmpty;
          return newSelector;
        }
      }, {
        key: "getElements",
        value: function getElements(els) {
          if (!els) {
            return [new Element('', '&', false, this._index, this._fileInfo)];
          }
  
          if (typeof els === 'string') {
            this.parse.parseNode(els, ['selector'], this._index, this._fileInfo, function (err, result) {
              if (err) {
                throw new LessError({
                  index: err.index,
                  message: err.message
                }, this.parse.imports, this._fileInfo.filename);
              }
  
              els = result[0].elements;
            });
          }
  
          return els;
        }
      }, {
        key: "createEmptySelectors",
        value: function createEmptySelectors() {
          var el = new Element('', '&', false, this._index, this._fileInfo);
          var sels = [new Selector([el], null, null, this._index, this._fileInfo)];
          sels[0].mediaEmpty = true;
          return sels;
        }
      }, {
        key: "match",
        value: function match(other) {
          var elements = this.elements;
          var len = elements.length;
          var olen;
          var i;
          other = other.mixinElements();
          olen = other.length;
  
          if (olen === 0 || len < olen) {
            return 0;
          } else {
            for (i = 0; i < olen; i++) {
              if (elements[i].value !== other[i]) {
                return 0;
              }
            }
          }
  
          return olen; // return number of matched elements
        }
      }, {
        key: "mixinElements",
        value: function mixinElements() {
          if (this.mixinElements_) {
            return this.mixinElements_;
          }
  
          var elements = this.elements.map(function (v) {
            return v.combinator.value + (v.value.value || v.value);
          }).join('').match(/[,&#\*\.\w-]([\w-]|(\\.))*/g);
  
          if (elements) {
            if (elements[0] === '&') {
              elements.shift();
            }
          } else {
            elements = [];
          }
  
          return this.mixinElements_ = elements;
        }
      }, {
        key: "isJustParentSelector",
        value: function isJustParentSelector() {
          return !this.mediaEmpty && this.elements.length === 1 && this.elements[0].value === '&' && (this.elements[0].combinator.value === ' ' || this.elements[0].combinator.value === '');
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var evaldCondition = this.condition && this.condition.eval(context);
          var elements = this.elements;
          var extendList = this.extendList;
          elements = elements && elements.map(function (e) {
            return e.eval(context);
          });
          extendList = extendList && extendList.map(function (extend) {
            return extend.eval(context);
          });
          return this.createDerived(elements, extendList, evaldCondition);
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          var i;
          var element;
  
          if ((!context || !context.firstSelector) && this.elements[0].combinator.value === '') {
            output.add(' ', this.fileInfo(), this.getIndex());
          }
  
          for (i = 0; i < this.elements.length; i++) {
            element = this.elements[i];
            element.genCSS(context, output);
          }
        }
      }, {
        key: "getIsOutput",
        value: function getIsOutput() {
          return this.evaldCondition;
        }
      }]);
  
      return Selector;
    }(Node);
  
    Selector.prototype.type = 'Selector';
  
    var Value =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Value, _Node);
  
      function Value(value) {
        var _this;
  
        _classCallCheck(this, Value);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Value).call(this));
  
        if (!value) {
          throw new Error('Value requires an array argument');
        }
  
        if (!Array.isArray(value)) {
          _this.value = [value];
        } else {
          _this.value = value;
        }
  
        return _this;
      }
  
      _createClass(Value, [{
        key: "accept",
        value: function accept(visitor) {
          if (this.value) {
            this.value = visitor.visitArray(this.value);
          }
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          if (this.value.length === 1) {
            return this.value[0].eval(context);
          } else {
            return new Value(this.value.map(function (v) {
              return v.eval(context);
            }));
          }
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          var i;
  
          for (i = 0; i < this.value.length; i++) {
            this.value[i].genCSS(context, output);
  
            if (i + 1 < this.value.length) {
              output.add(context && context.compress ? ',' : ', ');
            }
          }
        }
      }]);
  
      return Value;
    }(Node);
  
    Value.prototype.type = 'Value';
  
    var Keyword =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Keyword, _Node);
  
      function Keyword(value) {
        var _this;
  
        _classCallCheck(this, Keyword);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Keyword).call(this));
        _this.value = value;
        return _this;
      }
  
      _createClass(Keyword, [{
        key: "genCSS",
        value: function genCSS(context, output) {
          if (this.value === '%') {
            throw {
              type: 'Syntax',
              message: 'Invalid % without number'
            };
          }
  
          output.add(this.value);
        }
      }]);
  
      return Keyword;
    }(Node);
  
    Keyword.prototype.type = 'Keyword';
    Keyword.True = new Keyword('true');
    Keyword.False = new Keyword('false');
  
    var Anonymous =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Anonymous, _Node);
  
      function Anonymous(value, index, currentFileInfo, mapLines, rulesetLike, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, Anonymous);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Anonymous).call(this));
        _this.value = value;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.mapLines = mapLines;
        _this.rulesetLike = typeof rulesetLike === 'undefined' ? false : rulesetLike;
        _this.allowRoot = true;
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        return _this;
      }
  
      _createClass(Anonymous, [{
        key: "eval",
        value: function _eval() {
          return new Anonymous(this.value, this._index, this._fileInfo, this.mapLines, this.rulesetLike, this.visibilityInfo());
        }
      }, {
        key: "compare",
        value: function compare(other) {
          return other.toCSS && this.toCSS() === other.toCSS() ? 0 : undefined;
        }
      }, {
        key: "isRulesetLike",
        value: function isRulesetLike() {
          return this.rulesetLike;
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          this.nodeVisible = Boolean(this.value);
  
          if (this.nodeVisible) {
            output.add(this.value, this._fileInfo, this._index, this.mapLines);
          }
        }
      }]);
  
      return Anonymous;
    }(Node);
  
    Anonymous.prototype.type = 'Anonymous';
  
    var MATH = Math$1;
  
    var Declaration =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Declaration, _Node);
  
      function Declaration(name, value, important, merge, index, currentFileInfo, inline, variable) {
        var _this;
  
        _classCallCheck(this, Declaration);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Declaration).call(this));
        _this.name = name;
        _this.value = value instanceof Node ? value : new Value([value ? new Anonymous(value) : null]);
        _this.important = important ? " ".concat(important.trim()) : '';
        _this.merge = merge;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.inline = inline || false;
        _this.variable = variable !== undefined ? variable : name.charAt && name.charAt(0) === '@';
        _this.allowRoot = true;
  
        _this.setParent(_this.value, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(Declaration, [{
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add(this.name + (context.compress ? ':' : ': '), this.fileInfo(), this.getIndex());
  
          try {
            this.value.genCSS(context, output);
          } catch (e) {
            e.index = this._index;
            e.filename = this._fileInfo.filename;
            throw e;
          }
  
          output.add(this.important + (this.inline || context.lastRule && context.compress ? '' : ';'), this._fileInfo, this._index);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var mathBypass = false;
          var prevMath;
          var name = this.name;
          var evaldValue;
          var variable = this.variable;
  
          if (typeof name !== 'string') {
            // expand 'primitive' name directly to get
            // things faster (~10% for benchmark.less):
            name = name.length === 1 && name[0] instanceof Keyword ? name[0].value : evalName(context, name);
            variable = false; // never treat expanded interpolation as new variable name
          } // @todo remove when parens-division is default
  
  
          if (name === 'font' && context.math === MATH.ALWAYS) {
            mathBypass = true;
            prevMath = context.math;
            context.math = MATH.PARENS_DIVISION;
          }
  
          try {
            context.importantScope.push({});
            evaldValue = this.value.eval(context);
  
            if (!this.variable && evaldValue.type === 'DetachedRuleset') {
              throw {
                message: 'Rulesets cannot be evaluated on a property.',
                index: this.getIndex(),
                filename: this.fileInfo().filename
              };
            }
  
            var important = this.important;
            var importantResult = context.importantScope.pop();
  
            if (!important && importantResult.important) {
              important = importantResult.important;
            }
  
            return new Declaration(name, evaldValue, important, this.merge, this.getIndex(), this.fileInfo(), this.inline, variable);
          } catch (e) {
            if (typeof e.index !== 'number') {
              e.index = this.getIndex();
              e.filename = this.fileInfo().filename;
            }
  
            throw e;
          } finally {
            if (mathBypass) {
              context.math = prevMath;
            }
          }
        }
      }, {
        key: "makeImportant",
        value: function makeImportant() {
          return new Declaration(this.name, this.value, '!important', this.merge, this.getIndex(), this.fileInfo(), this.inline);
        }
      }]);
  
      return Declaration;
    }(Node);
  
    function evalName(context, name) {
      var value = '';
      var i;
      var n = name.length;
      var output = {
        add: function add(s) {
          value += s;
        }
      };
  
      for (i = 0; i < n; i++) {
        name[i].eval(context).genCSS(context, output);
      }
  
      return value;
    }
  
    Declaration.prototype.type = 'Declaration';
  
    var debugInfo = function debugInfo(context, ctx, lineSeparator) {
      var result = '';
  
      if (context.dumpLineNumbers && !context.compress) {
        switch (context.dumpLineNumbers) {
          case 'comments':
            result = debugInfo.asComment(ctx);
            break;
  
          case 'mediaquery':
            result = debugInfo.asMediaQuery(ctx);
            break;
  
          case 'all':
            result = debugInfo.asComment(ctx) + (lineSeparator || '') + debugInfo.asMediaQuery(ctx);
            break;
        }
      }
  
      return result;
    };
  
    debugInfo.asComment = function (ctx) {
      return "/* line ".concat(ctx.debugInfo.lineNumber, ", ").concat(ctx.debugInfo.fileName, " */\n");
    };
  
    debugInfo.asMediaQuery = function (ctx) {
      var filenameWithProtocol = ctx.debugInfo.fileName;
  
      if (!/^[a-z]+:\/\//i.test(filenameWithProtocol)) {
        filenameWithProtocol = "file://".concat(filenameWithProtocol);
      }
  
      return "@media -sass-debug-info{filename{font-family:".concat(filenameWithProtocol.replace(/([.:\/\\])/g, function (a) {
        if (a == '\\') {
          a = '\/';
        }
  
        return "\\".concat(a);
      }), "}line{font-family:\\00003").concat(ctx.debugInfo.lineNumber, "}}\n");
    };
  
    var Comment =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Comment, _Node);
  
      function Comment(value, isLineComment, index, currentFileInfo) {
        var _this;
  
        _classCallCheck(this, Comment);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Comment).call(this));
        _this.value = value;
        _this.isLineComment = isLineComment;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.allowRoot = true;
        return _this;
      }
  
      _createClass(Comment, [{
        key: "genCSS",
        value: function genCSS(context, output) {
          if (this.debugInfo) {
            output.add(debugInfo(context, this), this.fileInfo(), this.getIndex());
          }
  
          output.add(this.value);
        }
      }, {
        key: "isSilent",
        value: function isSilent(context) {
          var isCompressed = context.compress && this.value[2] !== '!';
          return this.isLineComment || isCompressed;
        }
      }]);
  
      return Comment;
    }(Node);
  
    Comment.prototype.type = 'Comment';
  
    var contexts = {};
  
    var copyFromOriginal = function copyFromOriginal(original, destination, propertiesToCopy) {
      if (!original) {
        return;
      }
  
      for (var i = 0; i < propertiesToCopy.length; i++) {
        if (original.hasOwnProperty(propertiesToCopy[i])) {
          destination[propertiesToCopy[i]] = original[propertiesToCopy[i]];
        }
      }
    };
    /*
     parse is used whilst parsing
     */
  
  
    var parseCopyProperties = [// options
    'paths', // option - unmodified - paths to search for imports on
    'rewriteUrls', // option - whether to adjust URL's to be relative
    'rootpath', // option - rootpath to append to URL's
    'strictImports', // option -
    'insecure', // option - whether to allow imports from insecure ssl hosts
    'dumpLineNumbers', // option - whether to dump line numbers
    'compress', // option - whether to compress
    'syncImport', // option - whether to import synchronously
    'chunkInput', // option - whether to chunk input. more performant but causes parse issues.
    'mime', // browser only - mime type for sheet import
    'useFileCache', // browser only - whether to use the per file session cache
    // context
    'processImports', // option & context - whether to process imports. if false then imports will not be imported.
    // Used by the import manager to stop multiple import visitors being created.
    'pluginManager' // Used as the plugin manager for the session
    ];
  
    contexts.Parse = function (options) {
      copyFromOriginal(options, this, parseCopyProperties);
  
      if (typeof this.paths === 'string') {
        this.paths = [this.paths];
      }
    };
  
    var evalCopyProperties = ['paths', // additional include paths
    'compress', // whether to compress
    'math', // whether math has to be within parenthesis
    'strictUnits', // whether units need to evaluate correctly
    'sourceMap', // whether to output a source map
    'importMultiple', // whether we are currently importing multiple copies
    'urlArgs', // whether to add args into url tokens
    'javascriptEnabled', // option - whether Inline JavaScript is enabled. if undefined, defaults to false
    'pluginManager', // Used as the plugin manager for the session
    'importantScope', // used to bubble up !important statements
    'rewriteUrls' // option - whether to adjust URL's to be relative
    ];
  
    function isPathRelative(path) {
      return !/^(?:[a-z-]+:|\/|#)/i.test(path);
    }
  
    function isPathLocalRelative(path) {
      return path.charAt(0) === '.';
    }
  
    contexts.Eval =
    /*#__PURE__*/
    function () {
      function _class(options, frames) {
        _classCallCheck(this, _class);
  
        copyFromOriginal(options, this, evalCopyProperties);
  
        if (typeof this.paths === 'string') {
          this.paths = [this.paths];
        }
  
        this.frames = frames || [];
        this.importantScope = this.importantScope || [];
        this.inCalc = false;
        this.mathOn = true;
      }
  
      _createClass(_class, [{
        key: "enterCalc",
        value: function enterCalc() {
          if (!this.calcStack) {
            this.calcStack = [];
          }
  
          this.calcStack.push(true);
          this.inCalc = true;
        }
      }, {
        key: "exitCalc",
        value: function exitCalc() {
          this.calcStack.pop();
  
          if (!this.calcStack) {
            this.inCalc = false;
          }
        }
      }, {
        key: "inParenthesis",
        value: function inParenthesis() {
          if (!this.parensStack) {
            this.parensStack = [];
          }
  
          this.parensStack.push(true);
        }
      }, {
        key: "outOfParenthesis",
        value: function outOfParenthesis() {
          this.parensStack.pop();
        }
      }, {
        key: "isMathOn",
        value: function isMathOn(op) {
          if (!this.mathOn) {
            return false;
          }
  
          if (op === '/' && this.math !== Math$1.ALWAYS && (!this.parensStack || !this.parensStack.length)) {
            return false;
          }
  
          if (this.math > Math$1.PARENS_DIVISION) {
            return this.parensStack && this.parensStack.length;
          }
  
          return true;
        }
      }, {
        key: "pathRequiresRewrite",
        value: function pathRequiresRewrite(path) {
          var isRelative = this.rewriteUrls === RewriteUrls.LOCAL ? isPathLocalRelative : isPathRelative;
          return isRelative(path);
        }
      }, {
        key: "rewritePath",
        value: function rewritePath(path, rootpath) {
          var newPath;
          rootpath = rootpath || '';
          newPath = this.normalizePath(rootpath + path); // If a path was explicit relative and the rootpath was not an absolute path
          // we must ensure that the new path is also explicit relative.
  
          if (isPathLocalRelative(path) && isPathRelative(rootpath) && isPathLocalRelative(newPath) === false) {
            newPath = "./".concat(newPath);
          }
  
          return newPath;
        }
      }, {
        key: "normalizePath",
        value: function normalizePath(path) {
          var segments = path.split('/').reverse();
          var segment;
          path = [];
  
          while (segments.length !== 0) {
            segment = segments.pop();
  
            switch (segment) {
              case '.':
                break;
  
              case '..':
                if (path.length === 0 || path[path.length - 1] === '..') {
                  path.push(segment);
                } else {
                  path.pop();
                }
  
                break;
  
              default:
                path.push(segment);
                break;
            }
          }
  
          return path.join('/');
        }
      }]);
  
      return _class;
    }();
  
    function makeRegistry(base) {
      return {
        _data: {},
        add: function add(name, func) {
          // precautionary case conversion, as later querying of
          // the registry by function-caller uses lower case as well.
          name = name.toLowerCase();
  
          if (this._data.hasOwnProperty(name)) ;
  
          this._data[name] = func;
        },
        addMultiple: function addMultiple(functions) {
          var _this = this;
  
          Object.keys(functions).forEach(function (name) {
            _this.add(name, functions[name]);
          });
        },
        get: function get(name) {
          return this._data[name] || base && base.get(name);
        },
        getLocalFunctions: function getLocalFunctions() {
          return this._data;
        },
        inherit: function inherit() {
          return makeRegistry(this);
        },
        create: function create(base) {
          return makeRegistry(base);
        }
      };
    }
  
    var functionRegistry = makeRegistry(null);
  
    var defaultFunc = {
      eval: function _eval() {
        var v = this.value_;
        var e = this.error_;
  
        if (e) {
          throw e;
        }
  
        if (v != null) {
          return v ? Keyword.True : Keyword.False;
        }
      },
      value: function value(v) {
        this.value_ = v;
      },
      error: function error(e) {
        this.error_ = e;
      },
      reset: function reset() {
        this.value_ = this.error_ = null;
      }
    };
  
    var Ruleset =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Ruleset, _Node);
  
      function Ruleset(selectors, rules, strictImports, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, Ruleset);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Ruleset).call(this));
        _this.selectors = selectors;
        _this.rules = rules;
        _this._lookups = {};
        _this._variables = null;
        _this._properties = null;
        _this.strictImports = strictImports;
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        _this.allowRoot = true;
  
        _this.setParent(_this.selectors, _assertThisInitialized(_this));
  
        _this.setParent(_this.rules, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(Ruleset, [{
        key: "isRulesetLike",
        value: function isRulesetLike() {
          return true;
        }
      }, {
        key: "accept",
        value: function accept(visitor) {
          if (this.paths) {
            this.paths = visitor.visitArray(this.paths, true);
          } else if (this.selectors) {
            this.selectors = visitor.visitArray(this.selectors);
          }
  
          if (this.rules && this.rules.length) {
            this.rules = visitor.visitArray(this.rules);
          }
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var selectors;
          var selCnt;
          var selector;
          var i;
          var hasVariable;
          var hasOnePassingSelector = false;
  
          if (this.selectors && (selCnt = this.selectors.length)) {
            selectors = new Array(selCnt);
            defaultFunc.error({
              type: 'Syntax',
              message: 'it is currently only allowed in parametric mixin guards,'
            });
  
            for (i = 0; i < selCnt; i++) {
              selector = this.selectors[i].eval(context);
  
              for (var j = 0; j < selector.elements.length; j++) {
                if (selector.elements[j].isVariable) {
                  hasVariable = true;
                  break;
                }
              }
  
              selectors[i] = selector;
  
              if (selector.evaldCondition) {
                hasOnePassingSelector = true;
              }
            }
  
            if (hasVariable) {
              var toParseSelectors = new Array(selCnt);
  
              for (i = 0; i < selCnt; i++) {
                selector = selectors[i];
                toParseSelectors[i] = selector.toCSS(context);
              }
  
              this.parse.parseNode(toParseSelectors.join(','), ["selectors"], selectors[0].getIndex(), selectors[0].fileInfo(), function (err, result) {
                if (result) {
                  selectors = flattenArray(result);
                }
              });
            }
  
            defaultFunc.reset();
          } else {
            hasOnePassingSelector = true;
          }
  
          var rules = this.rules ? copyArray(this.rules) : null;
          var ruleset = new Ruleset(selectors, rules, this.strictImports, this.visibilityInfo());
          var rule;
          var subRule;
          ruleset.originalRuleset = this;
          ruleset.root = this.root;
          ruleset.firstRoot = this.firstRoot;
          ruleset.allowImports = this.allowImports;
  
          if (this.debugInfo) {
            ruleset.debugInfo = this.debugInfo;
          }
  
          if (!hasOnePassingSelector) {
            rules.length = 0;
          } // inherit a function registry from the frames stack when possible;
          // otherwise from the global registry
  
  
          ruleset.functionRegistry = function (frames) {
            var i = 0;
            var n = frames.length;
            var found;
  
            for (; i !== n; ++i) {
              found = frames[i].functionRegistry;
  
              if (found) {
                return found;
              }
            }
  
            return functionRegistry;
          }(context.frames).inherit(); // push the current ruleset to the frames stack
  
  
          var ctxFrames = context.frames;
          ctxFrames.unshift(ruleset); // currrent selectors
  
          var ctxSelectors = context.selectors;
  
          if (!ctxSelectors) {
            context.selectors = ctxSelectors = [];
          }
  
          ctxSelectors.unshift(this.selectors); // Evaluate imports
  
          if (ruleset.root || ruleset.allowImports || !ruleset.strictImports) {
            ruleset.evalImports(context);
          } // Store the frames around mixin definitions,
          // so they can be evaluated like closures when the time comes.
  
  
          var rsRules = ruleset.rules;
  
          for (i = 0; rule = rsRules[i]; i++) {
            if (rule.evalFirst) {
              rsRules[i] = rule.eval(context);
            }
          }
  
          var mediaBlockCount = context.mediaBlocks && context.mediaBlocks.length || 0; // Evaluate mixin calls.
  
          for (i = 0; rule = rsRules[i]; i++) {
            if (rule.type === 'MixinCall') {
              /* jshint loopfunc:true */
              rules = rule.eval(context).filter(function (r) {
                if (r instanceof Declaration && r.variable) {
                  // do not pollute the scope if the variable is
                  // already there. consider returning false here
                  // but we need a way to "return" variable from mixins
                  return !ruleset.variable(r.name);
                }
  
                return true;
              });
              rsRules.splice.apply(rsRules, _toConsumableArray([i, 1].concat(rules)));
              i += rules.length - 1;
              ruleset.resetCache();
            } else if (rule.type === 'VariableCall') {
              /* jshint loopfunc:true */
              rules = rule.eval(context).rules.filter(function (r) {
                if (r instanceof Declaration && r.variable) {
                  // do not pollute the scope at all
                  return false;
                }
  
                return true;
              });
              rsRules.splice.apply(rsRules, _toConsumableArray([i, 1].concat(rules)));
              i += rules.length - 1;
              ruleset.resetCache();
            }
          } // Evaluate everything else
  
  
          for (i = 0; rule = rsRules[i]; i++) {
            if (!rule.evalFirst) {
              rsRules[i] = rule = rule.eval ? rule.eval(context) : rule;
            }
          } // Evaluate everything else
  
  
          for (i = 0; rule = rsRules[i]; i++) {
            // for rulesets, check if it is a css guard and can be removed
            if (rule instanceof Ruleset && rule.selectors && rule.selectors.length === 1) {
              // check if it can be folded in (e.g. & where)
              if (rule.selectors[0] && rule.selectors[0].isJustParentSelector()) {
                rsRules.splice(i--, 1);
  
                for (var j = 0; subRule = rule.rules[j]; j++) {
                  if (subRule instanceof Node) {
                    subRule.copyVisibilityInfo(rule.visibilityInfo());
  
                    if (!(subRule instanceof Declaration) || !subRule.variable) {
                      rsRules.splice(++i, 0, subRule);
                    }
                  }
                }
              }
            }
          } // Pop the stack
  
  
          ctxFrames.shift();
          ctxSelectors.shift();
  
          if (context.mediaBlocks) {
            for (i = mediaBlockCount; i < context.mediaBlocks.length; i++) {
              context.mediaBlocks[i].bubbleSelectors(selectors);
            }
          }
  
          return ruleset;
        }
      }, {
        key: "evalImports",
        value: function evalImports(context) {
          var rules = this.rules;
          var i;
          var importRules;
  
          if (!rules) {
            return;
          }
  
          for (i = 0; i < rules.length; i++) {
            if (rules[i].type === 'Import') {
              importRules = rules[i].eval(context);
  
              if (importRules && (importRules.length || importRules.length === 0)) {
                rules.splice.apply(rules, _toConsumableArray([i, 1].concat(importRules)));
                i += importRules.length - 1;
              } else {
                rules.splice(i, 1, importRules);
              }
  
              this.resetCache();
            }
          }
        }
      }, {
        key: "makeImportant",
        value: function makeImportant() {
          var result = new Ruleset(this.selectors, this.rules.map(function (r) {
            if (r.makeImportant) {
              return r.makeImportant();
            } else {
              return r;
            }
          }), this.strictImports, this.visibilityInfo());
          return result;
        }
      }, {
        key: "matchArgs",
        value: function matchArgs(args) {
          return !args || args.length === 0;
        } // lets you call a css selector with a guard
  
      }, {
        key: "matchCondition",
        value: function matchCondition(args, context) {
          var lastSelector = this.selectors[this.selectors.length - 1];
  
          if (!lastSelector.evaldCondition) {
            return false;
          }
  
          if (lastSelector.condition && !lastSelector.condition.eval(new contexts.Eval(context, context.frames))) {
            return false;
          }
  
          return true;
        }
      }, {
        key: "resetCache",
        value: function resetCache() {
          this._rulesets = null;
          this._variables = null;
          this._properties = null;
          this._lookups = {};
        }
      }, {
        key: "variables",
        value: function variables() {
          if (!this._variables) {
            this._variables = !this.rules ? {} : this.rules.reduce(function (hash, r) {
              if (r instanceof Declaration && r.variable === true) {
                hash[r.name] = r;
              } // when evaluating variables in an import statement, imports have not been eval'd
              // so we need to go inside import statements.
              // guard against root being a string (in the case of inlined less)
  
  
              if (r.type === 'Import' && r.root && r.root.variables) {
                var vars = r.root.variables();
  
                for (var name in vars) {
                  if (vars.hasOwnProperty(name)) {
                    hash[name] = r.root.variable(name);
                  }
                }
              }
  
              return hash;
            }, {});
          }
  
          return this._variables;
        }
      }, {
        key: "properties",
        value: function properties() {
          if (!this._properties) {
            this._properties = !this.rules ? {} : this.rules.reduce(function (hash, r) {
              if (r instanceof Declaration && r.variable !== true) {
                var name = r.name.length === 1 && r.name[0] instanceof Keyword ? r.name[0].value : r.name; // Properties don't overwrite as they can merge
  
                if (!hash["$".concat(name)]) {
                  hash["$".concat(name)] = [r];
                } else {
                  hash["$".concat(name)].push(r);
                }
              }
  
              return hash;
            }, {});
          }
  
          return this._properties;
        }
      }, {
        key: "variable",
        value: function variable(name) {
          var decl = this.variables()[name];
  
          if (decl) {
            return this.parseValue(decl);
          }
        }
      }, {
        key: "property",
        value: function property(name) {
          var decl = this.properties()[name];
  
          if (decl) {
            return this.parseValue(decl);
          }
        }
      }, {
        key: "lastDeclaration",
        value: function lastDeclaration() {
          for (var i = this.rules.length; i > 0; i--) {
            var decl = this.rules[i - 1];
  
            if (decl instanceof Declaration) {
              return this.parseValue(decl);
            }
          }
        }
      }, {
        key: "parseValue",
        value: function parseValue(toParse) {
          var self = this;
  
          function transformDeclaration(decl) {
            if (decl.value instanceof Anonymous && !decl.parsed) {
              if (typeof decl.value.value === 'string') {
                this.parse.parseNode(decl.value.value, ['value', 'important'], decl.value.getIndex(), decl.fileInfo(), function (err, result) {
                  if (err) {
                    decl.parsed = true;
                  }
  
                  if (result) {
                    decl.value = result[0];
                    decl.important = result[1] || '';
                    decl.parsed = true;
                  }
                });
              } else {
                decl.parsed = true;
              }
  
              return decl;
            } else {
              return decl;
            }
          }
  
          if (!Array.isArray(toParse)) {
            return transformDeclaration.call(self, toParse);
          } else {
            var nodes = [];
            toParse.forEach(function (n) {
              nodes.push(transformDeclaration.call(self, n));
            });
            return nodes;
          }
        }
      }, {
        key: "rulesets",
        value: function rulesets() {
          if (!this.rules) {
            return [];
          }
  
          var filtRules = [];
          var rules = this.rules;
          var i;
          var rule;
  
          for (i = 0; rule = rules[i]; i++) {
            if (rule.isRuleset) {
              filtRules.push(rule);
            }
          }
  
          return filtRules;
        }
      }, {
        key: "prependRule",
        value: function prependRule(rule) {
          var rules = this.rules;
  
          if (rules) {
            rules.unshift(rule);
          } else {
            this.rules = [rule];
          }
  
          this.setParent(rule, this);
        }
      }, {
        key: "find",
        value: function find(selector) {
          var self = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : this;
          var filter = arguments.length > 2 ? arguments[2] : undefined;
          var rules = [];
          var match;
          var foundMixins;
          var key = selector.toCSS();
  
          if (key in this._lookups) {
            return this._lookups[key];
          }
  
          this.rulesets().forEach(function (rule) {
            if (rule !== self) {
              for (var j = 0; j < rule.selectors.length; j++) {
                match = selector.match(rule.selectors[j]);
  
                if (match) {
                  if (selector.elements.length > match) {
                    if (!filter || filter(rule)) {
                      foundMixins = rule.find(new Selector(selector.elements.slice(match)), self, filter);
  
                      for (var i = 0; i < foundMixins.length; ++i) {
                        foundMixins[i].path.push(rule);
                      }
  
                      Array.prototype.push.apply(rules, foundMixins);
                    }
                  } else {
                    rules.push({
                      rule: rule,
                      path: []
                    });
                  }
  
                  break;
                }
              }
            }
          });
          this._lookups[key] = rules;
          return rules;
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          var i;
          var j;
          var charsetRuleNodes = [];
          var ruleNodes = [];
          var // Line number debugging
          debugInfo$1;
          var rule;
          var path;
          context.tabLevel = context.tabLevel || 0;
  
          if (!this.root) {
            context.tabLevel++;
          }
  
          var tabRuleStr = context.compress ? '' : Array(context.tabLevel + 1).join('  ');
          var tabSetStr = context.compress ? '' : Array(context.tabLevel).join('  ');
          var sep;
          var charsetNodeIndex = 0;
          var importNodeIndex = 0;
  
          for (i = 0; rule = this.rules[i]; i++) {
            if (rule instanceof Comment) {
              if (importNodeIndex === i) {
                importNodeIndex++;
              }
  
              ruleNodes.push(rule);
            } else if (rule.isCharset && rule.isCharset()) {
              ruleNodes.splice(charsetNodeIndex, 0, rule);
              charsetNodeIndex++;
              importNodeIndex++;
            } else if (rule.type === 'Import') {
              ruleNodes.splice(importNodeIndex, 0, rule);
              importNodeIndex++;
            } else {
              ruleNodes.push(rule);
            }
          }
  
          ruleNodes = charsetRuleNodes.concat(ruleNodes); // If this is the root node, we don't render
          // a selector, or {}.
  
          if (!this.root) {
            debugInfo$1 = debugInfo(context, this, tabSetStr);
  
            if (debugInfo$1) {
              output.add(debugInfo$1);
              output.add(tabSetStr);
            }
  
            var paths = this.paths;
            var pathCnt = paths.length;
            var pathSubCnt;
            sep = context.compress ? ',' : ",\n".concat(tabSetStr);
  
            for (i = 0; i < pathCnt; i++) {
              path = paths[i];
  
              if (!(pathSubCnt = path.length)) {
                continue;
              }
  
              if (i > 0) {
                output.add(sep);
              }
  
              context.firstSelector = true;
              path[0].genCSS(context, output);
              context.firstSelector = false;
  
              for (j = 1; j < pathSubCnt; j++) {
                path[j].genCSS(context, output);
              }
            }
  
            output.add((context.compress ? '{' : ' {\n') + tabRuleStr);
          } // Compile rules and rulesets
  
  
          for (i = 0; rule = ruleNodes[i]; i++) {
            if (i + 1 === ruleNodes.length) {
              context.lastRule = true;
            }
  
            var currentLastRule = context.lastRule;
  
            if (rule.isRulesetLike(rule)) {
              context.lastRule = false;
            }
  
            if (rule.genCSS) {
              rule.genCSS(context, output);
            } else if (rule.value) {
              output.add(rule.value.toString());
            }
  
            context.lastRule = currentLastRule;
  
            if (!context.lastRule && rule.isVisible()) {
              output.add(context.compress ? '' : "\n".concat(tabRuleStr));
            } else {
              context.lastRule = false;
            }
          }
  
          if (!this.root) {
            output.add(context.compress ? '}' : "\n".concat(tabSetStr, "}"));
            context.tabLevel--;
          }
  
          if (!output.isEmpty() && !context.compress && this.firstRoot) {
            output.add('\n');
          }
        }
      }, {
        key: "joinSelectors",
        value: function joinSelectors(paths, context, selectors) {
          for (var s = 0; s < selectors.length; s++) {
            this.joinSelector(paths, context, selectors[s]);
          }
        }
      }, {
        key: "joinSelector",
        value: function joinSelector(paths, context, selector) {
          function createParenthesis(elementsToPak, originalElement) {
            var replacementParen;
            var j;
  
            if (elementsToPak.length === 0) {
              replacementParen = new Paren(elementsToPak[0]);
            } else {
              var insideParent = new Array(elementsToPak.length);
  
              for (j = 0; j < elementsToPak.length; j++) {
                insideParent[j] = new Element(null, elementsToPak[j], originalElement.isVariable, originalElement._index, originalElement._fileInfo);
              }
  
              replacementParen = new Paren(new Selector(insideParent));
            }
  
            return replacementParen;
          }
  
          function createSelector(containedElement, originalElement) {
            var element;
            var selector;
            element = new Element(null, containedElement, originalElement.isVariable, originalElement._index, originalElement._fileInfo);
            selector = new Selector([element]);
            return selector;
          } // joins selector path from `beginningPath` with selector path in `addPath`
          // `replacedElement` contains element that is being replaced by `addPath`
          // returns concatenated path
  
  
          function addReplacementIntoPath(beginningPath, addPath, replacedElement, originalSelector) {
            var newSelectorPath;
            var lastSelector;
            var newJoinedSelector; // our new selector path
  
            newSelectorPath = []; // construct the joined selector - if & is the first thing this will be empty,
            // if not newJoinedSelector will be the last set of elements in the selector
  
            if (beginningPath.length > 0) {
              newSelectorPath = copyArray(beginningPath);
              lastSelector = newSelectorPath.pop();
              newJoinedSelector = originalSelector.createDerived(copyArray(lastSelector.elements));
            } else {
              newJoinedSelector = originalSelector.createDerived([]);
            }
  
            if (addPath.length > 0) {
              // /deep/ is a CSS4 selector - (removed, so should deprecate)
              // that is valid without anything in front of it
              // so if the & does not have a combinator that is "" or " " then
              // and there is a combinator on the parent, then grab that.
              // this also allows + a { & .b { .a & { ... though not sure why you would want to do that
              var combinator = replacedElement.combinator;
              var parentEl = addPath[0].elements[0];
  
              if (combinator.emptyOrWhitespace && !parentEl.combinator.emptyOrWhitespace) {
                combinator = parentEl.combinator;
              } // join the elements so far with the first part of the parent
  
  
              newJoinedSelector.elements.push(new Element(combinator, parentEl.value, replacedElement.isVariable, replacedElement._index, replacedElement._fileInfo));
              newJoinedSelector.elements = newJoinedSelector.elements.concat(addPath[0].elements.slice(1));
            } // now add the joined selector - but only if it is not empty
  
  
            if (newJoinedSelector.elements.length !== 0) {
              newSelectorPath.push(newJoinedSelector);
            } // put together the parent selectors after the join (e.g. the rest of the parent)
  
  
            if (addPath.length > 1) {
              var restOfPath = addPath.slice(1);
              restOfPath = restOfPath.map(function (selector) {
                return selector.createDerived(selector.elements, []);
              });
              newSelectorPath = newSelectorPath.concat(restOfPath);
            }
  
            return newSelectorPath;
          } // joins selector path from `beginningPath` with every selector path in `addPaths` array
          // `replacedElement` contains element that is being replaced by `addPath`
          // returns array with all concatenated paths
  
  
          function addAllReplacementsIntoPath(beginningPath, addPaths, replacedElement, originalSelector, result) {
            var j;
  
            for (j = 0; j < beginningPath.length; j++) {
              var newSelectorPath = addReplacementIntoPath(beginningPath[j], addPaths, replacedElement, originalSelector);
              result.push(newSelectorPath);
            }
  
            return result;
          }
  
          function mergeElementsOnToSelectors(elements, selectors) {
            var i;
            var sel;
  
            if (elements.length === 0) {
              return;
            }
  
            if (selectors.length === 0) {
              selectors.push([new Selector(elements)]);
              return;
            }
  
            for (i = 0; sel = selectors[i]; i++) {
              // if the previous thing in sel is a parent this needs to join on to it
              if (sel.length > 0) {
                sel[sel.length - 1] = sel[sel.length - 1].createDerived(sel[sel.length - 1].elements.concat(elements));
              } else {
                sel.push(new Selector(elements));
              }
            }
          } // replace all parent selectors inside `inSelector` by content of `context` array
          // resulting selectors are returned inside `paths` array
          // returns true if `inSelector` contained at least one parent selector
  
  
          function replaceParentSelector(paths, context, inSelector) {
            // The paths are [[Selector]]
            // The first list is a list of comma separated selectors
            // The inner list is a list of inheritance separated selectors
            // e.g.
            // .a, .b {
            //   .c {
            //   }
            // }
            // == [[.a] [.c]] [[.b] [.c]]
            //
            var i;
            var j;
            var k;
            var currentElements;
            var newSelectors;
            var selectorsMultiplied;
            var sel;
            var el;
            var hadParentSelector = false;
            var length;
            var lastSelector;
  
            function findNestedSelector(element) {
              var maybeSelector;
  
              if (!(element.value instanceof Paren)) {
                return null;
              }
  
              maybeSelector = element.value.value;
  
              if (!(maybeSelector instanceof Selector)) {
                return null;
              }
  
              return maybeSelector;
            } // the elements from the current selector so far
  
  
            currentElements = []; // the current list of new selectors to add to the path.
            // We will build it up. We initiate it with one empty selector as we "multiply" the new selectors
            // by the parents
  
            newSelectors = [[]];
  
            for (i = 0; el = inSelector.elements[i]; i++) {
              // non parent reference elements just get added
              if (el.value !== '&') {
                var nestedSelector = findNestedSelector(el);
  
                if (nestedSelector != null) {
                  // merge the current list of non parent selector elements
                  // on to the current list of selectors to add
                  mergeElementsOnToSelectors(currentElements, newSelectors);
                  var nestedPaths = [];
                  var replaced = void 0;
                  var replacedNewSelectors = [];
                  replaced = replaceParentSelector(nestedPaths, context, nestedSelector);
                  hadParentSelector = hadParentSelector || replaced; // the nestedPaths array should have only one member - replaceParentSelector does not multiply selectors
  
                  for (k = 0; k < nestedPaths.length; k++) {
                    var replacementSelector = createSelector(createParenthesis(nestedPaths[k], el), el);
                    addAllReplacementsIntoPath(newSelectors, [replacementSelector], el, inSelector, replacedNewSelectors);
                  }
  
                  newSelectors = replacedNewSelectors;
                  currentElements = [];
                } else {
                  currentElements.push(el);
                }
              } else {
                hadParentSelector = true; // the new list of selectors to add
  
                selectorsMultiplied = []; // merge the current list of non parent selector elements
                // on to the current list of selectors to add
  
                mergeElementsOnToSelectors(currentElements, newSelectors); // loop through our current selectors
  
                for (j = 0; j < newSelectors.length; j++) {
                  sel = newSelectors[j]; // if we don't have any parent paths, the & might be in a mixin so that it can be used
                  // whether there are parents or not
  
                  if (context.length === 0) {
                    // the combinator used on el should now be applied to the next element instead so that
                    // it is not lost
                    if (sel.length > 0) {
                      sel[0].elements.push(new Element(el.combinator, '', el.isVariable, el._index, el._fileInfo));
                    }
  
                    selectorsMultiplied.push(sel);
                  } else {
                    // and the parent selectors
                    for (k = 0; k < context.length; k++) {
                      // We need to put the current selectors
                      // then join the last selector's elements on to the parents selectors
                      var newSelectorPath = addReplacementIntoPath(sel, context[k], el, inSelector); // add that to our new set of selectors
  
                      selectorsMultiplied.push(newSelectorPath);
                    }
                  }
                } // our new selectors has been multiplied, so reset the state
  
  
                newSelectors = selectorsMultiplied;
                currentElements = [];
              }
            } // if we have any elements left over (e.g. .a& .b == .b)
            // add them on to all the current selectors
  
  
            mergeElementsOnToSelectors(currentElements, newSelectors);
  
            for (i = 0; i < newSelectors.length; i++) {
              length = newSelectors[i].length;
  
              if (length > 0) {
                paths.push(newSelectors[i]);
                lastSelector = newSelectors[i][length - 1];
                newSelectors[i][length - 1] = lastSelector.createDerived(lastSelector.elements, inSelector.extendList);
              }
            }
  
            return hadParentSelector;
          }
  
          function deriveSelector(visibilityInfo, deriveFrom) {
            var newSelector = deriveFrom.createDerived(deriveFrom.elements, deriveFrom.extendList, deriveFrom.evaldCondition);
            newSelector.copyVisibilityInfo(visibilityInfo);
            return newSelector;
          } // joinSelector code follows
  
  
          var i;
          var newPaths;
          var hadParentSelector;
          newPaths = [];
          hadParentSelector = replaceParentSelector(newPaths, context, selector);
  
          if (!hadParentSelector) {
            if (context.length > 0) {
              newPaths = [];
  
              for (i = 0; i < context.length; i++) {
                var concatenated = context[i].map(deriveSelector.bind(this, selector.visibilityInfo()));
                concatenated.push(selector);
                newPaths.push(concatenated);
              }
            } else {
              newPaths = [[selector]];
            }
          }
  
          for (i = 0; i < newPaths.length; i++) {
            paths.push(newPaths[i]);
          }
        }
      }]);
  
      return Ruleset;
    }(Node);
  
    Ruleset.prototype.type = 'Ruleset';
    Ruleset.prototype.isRuleset = true;
  
    var AtRule =
    /*#__PURE__*/
    function (_Node) {
      _inherits(AtRule, _Node);
  
      function AtRule(name, value, rules, index, currentFileInfo, debugInfo, isRooted, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, AtRule);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(AtRule).call(this));
        var i;
        _this.name = name;
        _this.value = value instanceof Node ? value : value ? new Anonymous(value) : value;
  
        if (rules) {
          if (Array.isArray(rules)) {
            _this.rules = rules;
          } else {
            _this.rules = [rules];
            _this.rules[0].selectors = new Selector([], null, null, index, currentFileInfo).createEmptySelectors();
          }
  
          for (i = 0; i < _this.rules.length; i++) {
            _this.rules[i].allowImports = true;
          }
  
          _this.setParent(_this.rules, _assertThisInitialized(_this));
        }
  
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.debugInfo = debugInfo;
        _this.isRooted = isRooted || false;
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        _this.allowRoot = true;
        return _this;
      }
  
      _createClass(AtRule, [{
        key: "accept",
        value: function accept(visitor) {
          var value = this.value;
          var rules = this.rules;
  
          if (rules) {
            this.rules = visitor.visitArray(rules);
          }
  
          if (value) {
            this.value = visitor.visit(value);
          }
        }
      }, {
        key: "isRulesetLike",
        value: function isRulesetLike() {
          return this.rules || !this.isCharset();
        }
      }, {
        key: "isCharset",
        value: function isCharset() {
          return '@charset' === this.name;
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          var value = this.value;
          var rules = this.rules;
          output.add(this.name, this.fileInfo(), this.getIndex());
  
          if (value) {
            output.add(' ');
            value.genCSS(context, output);
          }
  
          if (rules) {
            this.outputRuleset(context, output, rules);
          } else {
            output.add(';');
          }
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var mediaPathBackup;
          var mediaBlocksBackup;
          var value = this.value;
          var rules = this.rules; // media stored inside other atrule should not bubble over it
          // backpup media bubbling information
  
          mediaPathBackup = context.mediaPath;
          mediaBlocksBackup = context.mediaBlocks; // deleted media bubbling information
  
          context.mediaPath = [];
          context.mediaBlocks = [];
  
          if (value) {
            value = value.eval(context);
          }
  
          if (rules) {
            // assuming that there is only one rule at this point - that is how parser constructs the rule
            rules = [rules[0].eval(context)];
            rules[0].root = true;
          } // restore media bubbling information
  
  
          context.mediaPath = mediaPathBackup;
          context.mediaBlocks = mediaBlocksBackup;
          return new AtRule(this.name, value, rules, this.getIndex(), this.fileInfo(), this.debugInfo, this.isRooted, this.visibilityInfo());
        }
      }, {
        key: "variable",
        value: function variable(name) {
          if (this.rules) {
            // assuming that there is only one rule at this point - that is how parser constructs the rule
            return Ruleset.prototype.variable.call(this.rules[0], name);
          }
        }
      }, {
        key: "find",
        value: function find() {
          if (this.rules) {
            for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
              args[_key] = arguments[_key];
            }
  
            // assuming that there is only one rule at this point - that is how parser constructs the rule
            return Ruleset.prototype.find.apply(this.rules[0], args);
          }
        }
      }, {
        key: "rulesets",
        value: function rulesets() {
          if (this.rules) {
            // assuming that there is only one rule at this point - that is how parser constructs the rule
            return Ruleset.prototype.rulesets.apply(this.rules[0]);
          }
        }
      }, {
        key: "outputRuleset",
        value: function outputRuleset(context, output, rules) {
          var ruleCnt = rules.length;
          var i;
          context.tabLevel = (context.tabLevel | 0) + 1; // Compressed
  
          if (context.compress) {
            output.add('{');
  
            for (i = 0; i < ruleCnt; i++) {
              rules[i].genCSS(context, output);
            }
  
            output.add('}');
            context.tabLevel--;
            return;
          } // Non-compressed
  
  
          var tabSetStr = "\n".concat(Array(context.tabLevel).join('  '));
          var tabRuleStr = "".concat(tabSetStr, "  ");
  
          if (!ruleCnt) {
            output.add(" {".concat(tabSetStr, "}"));
          } else {
            output.add(" {".concat(tabRuleStr));
            rules[0].genCSS(context, output);
  
            for (i = 1; i < ruleCnt; i++) {
              output.add(tabRuleStr);
              rules[i].genCSS(context, output);
            }
  
            output.add("".concat(tabSetStr, "}"));
          }
  
          context.tabLevel--;
        }
      }]);
  
      return AtRule;
    }(Node);
  
    AtRule.prototype.type = 'AtRule';
  
    var DetachedRuleset =
    /*#__PURE__*/
    function (_Node) {
      _inherits(DetachedRuleset, _Node);
  
      function DetachedRuleset(ruleset, frames) {
        var _this;
  
        _classCallCheck(this, DetachedRuleset);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(DetachedRuleset).call(this));
        _this.ruleset = ruleset;
        _this.frames = frames;
  
        _this.setParent(_this.ruleset, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(DetachedRuleset, [{
        key: "accept",
        value: function accept(visitor) {
          this.ruleset = visitor.visit(this.ruleset);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var frames = this.frames || copyArray(context.frames);
          return new DetachedRuleset(this.ruleset, frames);
        }
      }, {
        key: "callEval",
        value: function callEval(context) {
          return this.ruleset.eval(this.frames ? new contexts.Eval(context, this.frames.concat(context.frames)) : context);
        }
      }]);
  
      return DetachedRuleset;
    }(Node);
  
    DetachedRuleset.prototype.type = 'DetachedRuleset';
    DetachedRuleset.prototype.evalFirst = true;
  
    var Unit =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Unit, _Node);
  
      function Unit(numerator, denominator, backupUnit) {
        var _this;
  
        _classCallCheck(this, Unit);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Unit).call(this));
        _this.numerator = numerator ? copyArray(numerator).sort() : [];
        _this.denominator = denominator ? copyArray(denominator).sort() : [];
  
        if (backupUnit) {
          _this.backupUnit = backupUnit;
        } else if (numerator && numerator.length) {
          _this.backupUnit = numerator[0];
        }
  
        return _this;
      }
  
      _createClass(Unit, [{
        key: "clone",
        value: function clone() {
          return new Unit(copyArray(this.numerator), copyArray(this.denominator), this.backupUnit);
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          // Dimension checks the unit is singular and throws an error if in strict math mode.
          var strictUnits = context && context.strictUnits;
  
          if (this.numerator.length === 1) {
            output.add(this.numerator[0]); // the ideal situation
          } else if (!strictUnits && this.backupUnit) {
            output.add(this.backupUnit);
          } else if (!strictUnits && this.denominator.length) {
            output.add(this.denominator[0]);
          }
        }
      }, {
        key: "toString",
        value: function toString() {
          var i;
          var returnStr = this.numerator.join('*');
  
          for (i = 0; i < this.denominator.length; i++) {
            returnStr += "/".concat(this.denominator[i]);
          }
  
          return returnStr;
        }
      }, {
        key: "compare",
        value: function compare(other) {
          return this.is(other.toString()) ? 0 : undefined;
        }
      }, {
        key: "is",
        value: function is(unitString) {
          return this.toString().toUpperCase() === unitString.toUpperCase();
        }
      }, {
        key: "isLength",
        value: function isLength() {
          return RegExp('^(px|em|ex|ch|rem|in|cm|mm|pc|pt|ex|vw|vh|vmin|vmax)$', 'gi').test(this.toCSS());
        }
      }, {
        key: "isEmpty",
        value: function isEmpty() {
          return this.numerator.length === 0 && this.denominator.length === 0;
        }
      }, {
        key: "isSingular",
        value: function isSingular() {
          return this.numerator.length <= 1 && this.denominator.length === 0;
        }
      }, {
        key: "map",
        value: function map(callback) {
          var i;
  
          for (i = 0; i < this.numerator.length; i++) {
            this.numerator[i] = callback(this.numerator[i], false);
          }
  
          for (i = 0; i < this.denominator.length; i++) {
            this.denominator[i] = callback(this.denominator[i], true);
          }
        }
      }, {
        key: "usedUnits",
        value: function usedUnits() {
          var group;
          var result = {};
          var mapUnit;
          var groupName;
  
          mapUnit = function mapUnit(atomicUnit) {
            /* jshint loopfunc:true */
            if (group.hasOwnProperty(atomicUnit) && !result[groupName]) {
              result[groupName] = atomicUnit;
            }
  
            return atomicUnit;
          };
  
          for (groupName in unitConversions) {
            if (unitConversions.hasOwnProperty(groupName)) {
              group = unitConversions[groupName];
              this.map(mapUnit);
            }
          }
  
          return result;
        }
      }, {
        key: "cancel",
        value: function cancel() {
          var counter = {};
          var atomicUnit;
          var i;
  
          for (i = 0; i < this.numerator.length; i++) {
            atomicUnit = this.numerator[i];
            counter[atomicUnit] = (counter[atomicUnit] || 0) + 1;
          }
  
          for (i = 0; i < this.denominator.length; i++) {
            atomicUnit = this.denominator[i];
            counter[atomicUnit] = (counter[atomicUnit] || 0) - 1;
          }
  
          this.numerator = [];
          this.denominator = [];
  
          for (atomicUnit in counter) {
            if (counter.hasOwnProperty(atomicUnit)) {
              var count = counter[atomicUnit];
  
              if (count > 0) {
                for (i = 0; i < count; i++) {
                  this.numerator.push(atomicUnit);
                }
              } else if (count < 0) {
                for (i = 0; i < -count; i++) {
                  this.denominator.push(atomicUnit);
                }
              }
            }
          }
  
          this.numerator.sort();
          this.denominator.sort();
        }
      }]);
  
      return Unit;
    }(Node);
  
    Unit.prototype.type = 'Unit';
  
    // A number with a unit
    //
  
    var Dimension =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Dimension, _Node);
  
      function Dimension(value, unit) {
        var _this;
  
        _classCallCheck(this, Dimension);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Dimension).call(this));
        _this.value = parseFloat(value);
  
        if (isNaN(_this.value)) {
          throw new Error('Dimension is not a number.');
        }
  
        _this.unit = unit && unit instanceof Unit ? unit : new Unit(unit ? [unit] : undefined);
  
        _this.setParent(_this.unit, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(Dimension, [{
        key: "accept",
        value: function accept(visitor) {
          this.unit = visitor.visit(this.unit);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          return this;
        }
      }, {
        key: "toColor",
        value: function toColor() {
          return new Color([this.value, this.value, this.value]);
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          if (context && context.strictUnits && !this.unit.isSingular()) {
            throw new Error("Multiple units in dimension. Correct the units or use the unit function. Bad unit: ".concat(this.unit.toString()));
          }
  
          var value = this.fround(context, this.value);
          var strValue = String(value);
  
          if (value !== 0 && value < 0.000001 && value > -0.000001) {
            // would be output 1e-6 etc.
            strValue = value.toFixed(20).replace(/0+$/, '');
          }
  
          if (context && context.compress) {
            // Zero values doesn't need a unit
            if (value === 0 && this.unit.isLength()) {
              output.add(strValue);
              return;
            } // Float values doesn't need a leading zero
  
  
            if (value > 0 && value < 1) {
              strValue = strValue.substr(1);
            }
          }
  
          output.add(strValue);
          this.unit.genCSS(context, output);
        } // In an operation between two Dimensions,
        // we default to the first Dimension's unit,
        // so `1px + 2` will yield `3px`.
  
      }, {
        key: "operate",
        value: function operate(context, op, other) {
          /* jshint noempty:false */
          var value = this._operate(context, op, this.value, other.value);
  
          var unit = this.unit.clone();
  
          if (op === '+' || op === '-') {
            if (unit.numerator.length === 0 && unit.denominator.length === 0) {
              unit = other.unit.clone();
  
              if (this.unit.backupUnit) {
                unit.backupUnit = this.unit.backupUnit;
              }
            } else if (other.unit.numerator.length === 0 && unit.denominator.length === 0) ; else {
              other = other.convertTo(this.unit.usedUnits());
  
              if (context.strictUnits && other.unit.toString() !== unit.toString()) {
                throw new Error("Incompatible units. Change the units or use the unit function. " + "Bad units: '".concat(unit.toString(), "' and '").concat(other.unit.toString(), "'."));
              }
  
              value = this._operate(context, op, this.value, other.value);
            }
          } else if (op === '*') {
            unit.numerator = unit.numerator.concat(other.unit.numerator).sort();
            unit.denominator = unit.denominator.concat(other.unit.denominator).sort();
            unit.cancel();
          } else if (op === '/') {
            unit.numerator = unit.numerator.concat(other.unit.denominator).sort();
            unit.denominator = unit.denominator.concat(other.unit.numerator).sort();
            unit.cancel();
          }
  
          return new Dimension(value, unit);
        }
      }, {
        key: "compare",
        value: function compare(other) {
          var a;
          var b;
  
          if (!(other instanceof Dimension)) {
            return undefined;
          }
  
          if (this.unit.isEmpty() || other.unit.isEmpty()) {
            a = this;
            b = other;
          } else {
            a = this.unify();
            b = other.unify();
  
            if (a.unit.compare(b.unit) !== 0) {
              return undefined;
            }
          }
  
          return Node.numericCompare(a.value, b.value);
        }
      }, {
        key: "unify",
        value: function unify() {
          return this.convertTo({
            length: 'px',
            duration: 's',
            angle: 'rad'
          });
        }
      }, {
        key: "convertTo",
        value: function convertTo(conversions) {
          var value = this.value;
          var unit = this.unit.clone();
          var i;
          var groupName;
          var group;
          var targetUnit;
          var derivedConversions = {};
          var applyUnit;
  
          if (typeof conversions === 'string') {
            for (i in unitConversions) {
              if (unitConversions[i].hasOwnProperty(conversions)) {
                derivedConversions = {};
                derivedConversions[i] = conversions;
              }
            }
  
            conversions = derivedConversions;
          }
  
          applyUnit = function applyUnit(atomicUnit, denominator) {
            /* jshint loopfunc:true */
            if (group.hasOwnProperty(atomicUnit)) {
              if (denominator) {
                value = value / (group[atomicUnit] / group[targetUnit]);
              } else {
                value = value * (group[atomicUnit] / group[targetUnit]);
              }
  
              return targetUnit;
            }
  
            return atomicUnit;
          };
  
          for (groupName in conversions) {
            if (conversions.hasOwnProperty(groupName)) {
              targetUnit = conversions[groupName];
              group = unitConversions[groupName];
              unit.map(applyUnit);
            }
          }
  
          unit.cancel();
          return new Dimension(value, unit);
        }
      }]);
  
      return Dimension;
    }(Node);
  
    Dimension.prototype.type = 'Dimension';
  
    var MATH$1 = Math$1;
  
    var Operation =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Operation, _Node);
  
      function Operation(op, operands, isSpaced) {
        var _this;
  
        _classCallCheck(this, Operation);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Operation).call(this));
        _this.op = op.trim();
        _this.operands = operands;
        _this.isSpaced = isSpaced;
        return _this;
      }
  
      _createClass(Operation, [{
        key: "accept",
        value: function accept(visitor) {
          this.operands = visitor.visitArray(this.operands);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var a = this.operands[0].eval(context);
          var b = this.operands[1].eval(context);
          var op;
  
          if (context.isMathOn(this.op)) {
            op = this.op === './' ? '/' : this.op;
  
            if (a instanceof Dimension && b instanceof Color) {
              a = a.toColor();
            }
  
            if (b instanceof Dimension && a instanceof Color) {
              b = b.toColor();
            }
  
            if (!a.operate) {
              if (a instanceof Operation && a.op === '/' && context.math === MATH$1.PARENS_DIVISION) {
                return new Operation(this.op, [a, b], this.isSpaced);
              }
  
              throw {
                type: 'Operation',
                message: 'Operation on an invalid type'
              };
            }
  
            return a.operate(context, op, b);
          } else {
            return new Operation(this.op, [a, b], this.isSpaced);
          }
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          this.operands[0].genCSS(context, output);
  
          if (this.isSpaced) {
            output.add(' ');
          }
  
          output.add(this.op);
  
          if (this.isSpaced) {
            output.add(' ');
          }
  
          this.operands[1].genCSS(context, output);
        }
      }]);
  
      return Operation;
    }(Node);
  
    Operation.prototype.type = 'Operation';
  
    var MATH$2 = Math$1;
  
    var Expression =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Expression, _Node);
  
      function Expression(value, noSpacing) {
        var _this;
  
        _classCallCheck(this, Expression);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Expression).call(this));
        _this.value = value;
        _this.noSpacing = noSpacing;
  
        if (!value) {
          throw new Error('Expression requires an array parameter');
        }
  
        return _this;
      }
  
      _createClass(Expression, [{
        key: "accept",
        value: function accept(visitor) {
          this.value = visitor.visitArray(this.value);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var returnValue;
          var mathOn = context.isMathOn();
          var inParenthesis = this.parens && (context.math !== MATH$2.STRICT_LEGACY || !this.parensInOp);
          var doubleParen = false;
  
          if (inParenthesis) {
            context.inParenthesis();
          }
  
          if (this.value.length > 1) {
            returnValue = new Expression(this.value.map(function (e) {
              if (!e.eval) {
                return e;
              }
  
              return e.eval(context);
            }), this.noSpacing);
          } else if (this.value.length === 1) {
            if (this.value[0].parens && !this.value[0].parensInOp && !context.inCalc) {
              doubleParen = true;
            }
  
            returnValue = this.value[0].eval(context);
          } else {
            returnValue = this;
          }
  
          if (inParenthesis) {
            context.outOfParenthesis();
          }
  
          if (this.parens && this.parensInOp && !mathOn && !doubleParen && !(returnValue instanceof Dimension)) {
            returnValue = new Paren(returnValue);
          }
  
          return returnValue;
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          for (var i = 0; i < this.value.length; i++) {
            this.value[i].genCSS(context, output);
  
            if (!this.noSpacing && i + 1 < this.value.length) {
              output.add(' ');
            }
          }
        }
      }, {
        key: "throwAwayComments",
        value: function throwAwayComments() {
          this.value = this.value.filter(function (v) {
            return !(v instanceof Comment);
          });
        }
      }]);
  
      return Expression;
    }(Node);
  
    Expression.prototype.type = 'Expression';
  
    var functionCaller =
    /*#__PURE__*/
    function () {
      function functionCaller(name, context, index, currentFileInfo) {
        _classCallCheck(this, functionCaller);
  
        this.name = name.toLowerCase();
        this.index = index;
        this.context = context;
        this.currentFileInfo = currentFileInfo;
        this.func = context.frames[0].functionRegistry.get(this.name);
      }
  
      _createClass(functionCaller, [{
        key: "isValid",
        value: function isValid() {
          return Boolean(this.func);
        }
      }, {
        key: "call",
        value: function call(args) {
          // This code is terrible and should be replaced as per this issue...
          // https://github.com/less/less.js/issues/2477
          if (Array.isArray(args)) {
            args = args.filter(function (item) {
              if (item.type === 'Comment') {
                return false;
              }
  
              return true;
            }).map(function (item) {
              if (item.type === 'Expression') {
                var subNodes = item.value.filter(function (item) {
                  if (item.type === 'Comment') {
                    return false;
                  }
  
                  return true;
                });
  
                if (subNodes.length === 1) {
                  return subNodes[0];
                } else {
                  return new Expression(subNodes);
                }
              }
  
              return item;
            });
          }
  
          return this.func.apply(this, _toConsumableArray(args));
        }
      }]);
  
      return functionCaller;
    }();
  
    // A function call node.
    //
  
    var Call =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Call, _Node);
  
      function Call(name, args, index, currentFileInfo) {
        var _this;
  
        _classCallCheck(this, Call);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Call).call(this));
        _this.name = name;
        _this.args = args;
        _this.calc = name === 'calc';
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        return _this;
      }
  
      _createClass(Call, [{
        key: "accept",
        value: function accept(visitor) {
          if (this.args) {
            this.args = visitor.visitArray(this.args);
          }
        } //
        // When evaluating a function call,
        // we either find the function in the functionRegistry,
        // in which case we call it, passing the  evaluated arguments,
        // if this returns null or we cannot find the function, we
        // simply print it out as it appeared originally [2].
        //
        // The reason why we evaluate the arguments, is in the case where
        // we try to pass a variable to a function, like: `saturate(@color)`.
        // The function should receive the value, not the variable.
        //
  
      }, {
        key: "eval",
        value: function _eval(context) {
          /**
           * Turn off math for calc(), and switch back on for evaluating nested functions
           */
          var currentMathContext = context.mathOn;
          context.mathOn = !this.calc;
  
          if (this.calc || context.inCalc) {
            context.enterCalc();
          }
  
          var args = this.args.map(function (a) {
            return a.eval(context);
          });
  
          if (this.calc || context.inCalc) {
            context.exitCalc();
          }
  
          context.mathOn = currentMathContext;
          var result;
          var funcCaller = new functionCaller(this.name, context, this.getIndex(), this.fileInfo());
  
          if (funcCaller.isValid()) {
            try {
              result = funcCaller.call(args);
            } catch (e) {
              throw {
                type: e.type || 'Runtime',
                message: "error evaluating function `".concat(this.name, "`").concat(e.message ? ": ".concat(e.message) : ''),
                index: this.getIndex(),
                filename: this.fileInfo().filename,
                line: e.lineNumber,
                column: e.columnNumber
              };
            }
  
            if (result !== null && result !== undefined) {
              // Results that that are not nodes are cast as Anonymous nodes
              // Falsy values or booleans are returned as empty nodes
              if (!(result instanceof Node)) {
                if (!result || result === true) {
                  result = new Anonymous(null);
                } else {
                  result = new Anonymous(result.toString());
                }
              }
  
              result._index = this._index;
              result._fileInfo = this._fileInfo;
              return result;
            }
          }
  
          return new Call(this.name, args, this.getIndex(), this.fileInfo());
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add("".concat(this.name, "("), this.fileInfo(), this.getIndex());
  
          for (var i = 0; i < this.args.length; i++) {
            this.args[i].genCSS(context, output);
  
            if (i + 1 < this.args.length) {
              output.add(', ');
            }
          }
  
          output.add(')');
        }
      }]);
  
      return Call;
    }(Node);
  
    Call.prototype.type = 'Call';
  
    var Variable =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Variable, _Node);
  
      function Variable(name, index, currentFileInfo) {
        var _this;
  
        _classCallCheck(this, Variable);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Variable).call(this));
        _this.name = name;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        return _this;
      }
  
      _createClass(Variable, [{
        key: "eval",
        value: function _eval(context) {
          var variable;
          var name = this.name;
  
          if (name.indexOf('@@') === 0) {
            name = "@".concat(new Variable(name.slice(1), this.getIndex(), this.fileInfo()).eval(context).value);
          }
  
          if (this.evaluating) {
            throw {
              type: 'Name',
              message: "Recursive variable definition for ".concat(name),
              filename: this.fileInfo().filename,
              index: this.getIndex()
            };
          }
  
          this.evaluating = true;
          variable = this.find(context.frames, function (frame) {
            var v = frame.variable(name);
  
            if (v) {
              if (v.important) {
                var importantScope = context.importantScope[context.importantScope.length - 1];
                importantScope.important = v.important;
              } // If in calc, wrap vars in a function call to cascade evaluate args first
  
  
              if (context.inCalc) {
                return new Call('_SELF', [v.value]).eval(context);
              } else {
                return v.value.eval(context);
              }
            }
          });
  
          if (variable) {
            this.evaluating = false;
            return variable;
          } else {
            throw {
              type: 'Name',
              message: "variable ".concat(name, " is undefined"),
              filename: this.fileInfo().filename,
              index: this.getIndex()
            };
          }
        }
      }, {
        key: "find",
        value: function find(obj, fun) {
          for (var i = 0, r; i < obj.length; i++) {
            r = fun.call(obj, obj[i]);
  
            if (r) {
              return r;
            }
          }
  
          return null;
        }
      }]);
  
      return Variable;
    }(Node);
  
    Variable.prototype.type = 'Variable';
  
    var Property =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Property, _Node);
  
      function Property(name, index, currentFileInfo) {
        var _this;
  
        _classCallCheck(this, Property);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Property).call(this));
        _this.name = name;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        return _this;
      }
  
      _createClass(Property, [{
        key: "eval",
        value: function _eval(context) {
          var property;
          var name = this.name; // TODO: shorten this reference
  
          var mergeRules = context.pluginManager.less.visitors.ToCSSVisitor.prototype._mergeRules;
  
          if (this.evaluating) {
            throw {
              type: 'Name',
              message: "Recursive property reference for ".concat(name),
              filename: this.fileInfo().filename,
              index: this.getIndex()
            };
          }
  
          this.evaluating = true;
          property = this.find(context.frames, function (frame) {
            var v;
            var vArr = frame.property(name);
  
            if (vArr) {
              for (var i = 0; i < vArr.length; i++) {
                v = vArr[i];
                vArr[i] = new Declaration(v.name, v.value, v.important, v.merge, v.index, v.currentFileInfo, v.inline, v.variable);
              }
  
              mergeRules(vArr);
              v = vArr[vArr.length - 1];
  
              if (v.important) {
                var importantScope = context.importantScope[context.importantScope.length - 1];
                importantScope.important = v.important;
              }
  
              v = v.value.eval(context);
              return v;
            }
          });
  
          if (property) {
            this.evaluating = false;
            return property;
          } else {
            throw {
              type: 'Name',
              message: "Property '".concat(name, "' is undefined"),
              filename: this.currentFileInfo.filename,
              index: this.index
            };
          }
        }
      }, {
        key: "find",
        value: function find(obj, fun) {
          for (var i = 0, r; i < obj.length; i++) {
            r = fun.call(obj, obj[i]);
  
            if (r) {
              return r;
            }
          }
  
          return null;
        }
      }]);
  
      return Property;
    }(Node);
  
    Property.prototype.type = 'Property';
  
    var Attribute =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Attribute, _Node);
  
      function Attribute(key, op, value) {
        var _this;
  
        _classCallCheck(this, Attribute);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Attribute).call(this));
        _this.key = key;
        _this.op = op;
        _this.value = value;
        return _this;
      }
  
      _createClass(Attribute, [{
        key: "eval",
        value: function _eval(context) {
          return new Attribute(this.key.eval ? this.key.eval(context) : this.key, this.op, this.value && this.value.eval ? this.value.eval(context) : this.value);
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add(this.toCSS(context));
        }
      }, {
        key: "toCSS",
        value: function toCSS(context) {
          var value = this.key.toCSS ? this.key.toCSS(context) : this.key;
  
          if (this.op) {
            value += this.op;
            value += this.value.toCSS ? this.value.toCSS(context) : this.value;
          }
  
          return "[".concat(value, "]");
        }
      }]);
  
      return Attribute;
    }(Node);
  
    Attribute.prototype.type = 'Attribute';
  
    var Quoted =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Quoted, _Node);
  
      function Quoted(str, content, escaped, index, currentFileInfo) {
        var _this;
  
        _classCallCheck(this, Quoted);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Quoted).call(this));
        _this.escaped = escaped == null ? true : escaped;
        _this.value = content || '';
        _this.quote = str.charAt(0);
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.variableRegex = /@\{([\w-]+)\}/g;
        _this.propRegex = /\$\{([\w-]+)\}/g;
        _this.allowRoot = escaped;
        return _this;
      }
  
      _createClass(Quoted, [{
        key: "genCSS",
        value: function genCSS(context, output) {
          if (!this.escaped) {
            output.add(this.quote, this.fileInfo(), this.getIndex());
          }
  
          output.add(this.value);
  
          if (!this.escaped) {
            output.add(this.quote);
          }
        }
      }, {
        key: "containsVariables",
        value: function containsVariables() {
          return this.value.match(this.variableRegex);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var that = this;
          var value = this.value;
  
          var variableReplacement = function variableReplacement(_, name) {
            var v = new Variable("@".concat(name), that.getIndex(), that.fileInfo()).eval(context, true);
            return v instanceof Quoted ? v.value : v.toCSS();
          };
  
          var propertyReplacement = function propertyReplacement(_, name) {
            var v = new Property("$".concat(name), that.getIndex(), that.fileInfo()).eval(context, true);
            return v instanceof Quoted ? v.value : v.toCSS();
          };
  
          function iterativeReplace(value, regexp, replacementFnc) {
            var evaluatedValue = value;
  
            do {
              value = evaluatedValue.toString();
              evaluatedValue = value.replace(regexp, replacementFnc);
            } while (value !== evaluatedValue);
  
            return evaluatedValue;
          }
  
          value = iterativeReplace(value, this.variableRegex, variableReplacement);
          value = iterativeReplace(value, this.propRegex, propertyReplacement);
          return new Quoted(this.quote + value + this.quote, value, this.escaped, this.getIndex(), this.fileInfo());
        }
      }, {
        key: "compare",
        value: function compare(other) {
          // when comparing quoted strings allow the quote to differ
          if (other.type === 'Quoted' && !this.escaped && !other.escaped) {
            return Node.numericCompare(this.value, other.value);
          } else {
            return other.toCSS && this.toCSS() === other.toCSS() ? 0 : undefined;
          }
        }
      }]);
  
      return Quoted;
    }(Node);
  
    Quoted.prototype.type = 'Quoted';
  
    var URL =
    /*#__PURE__*/
    function (_Node) {
      _inherits(URL, _Node);
  
      function URL(val, index, currentFileInfo, isEvald) {
        var _this;
  
        _classCallCheck(this, URL);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(URL).call(this));
        _this.value = val;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.isEvald = isEvald;
        return _this;
      }
  
      _createClass(URL, [{
        key: "accept",
        value: function accept(visitor) {
          this.value = visitor.visit(this.value);
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add('url(');
          this.value.genCSS(context, output);
          output.add(')');
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var val = this.value.eval(context);
          var rootpath;
  
          if (!this.isEvald) {
            // Add the rootpath if the URL requires a rewrite
            rootpath = this.fileInfo() && this.fileInfo().rootpath;
  
            if (typeof rootpath === 'string' && typeof val.value === 'string' && context.pathRequiresRewrite(val.value)) {
              if (!val.quote) {
                rootpath = escapePath(rootpath);
              }
  
              val.value = context.rewritePath(val.value, rootpath);
            } else {
              val.value = context.normalizePath(val.value);
            } // Add url args if enabled
  
  
            if (context.urlArgs) {
              if (!val.value.match(/^\s*data:/)) {
                var delimiter = val.value.indexOf('?') === -1 ? '?' : '&';
                var urlArgs = delimiter + context.urlArgs;
  
                if (val.value.indexOf('#') !== -1) {
                  val.value = val.value.replace('#', "".concat(urlArgs, "#"));
                } else {
                  val.value += urlArgs;
                }
              }
            }
          }
  
          return new URL(val, this.getIndex(), this.fileInfo(), true);
        }
      }]);
  
      return URL;
    }(Node);
  
    URL.prototype.type = 'Url';
  
    function escapePath(path) {
      return path.replace(/[\(\)'"\s]/g, function (match) {
        return "\\".concat(match);
      });
    }
  
    var Media =
    /*#__PURE__*/
    function (_AtRule) {
      _inherits(Media, _AtRule);
  
      function Media(value, features, index, currentFileInfo, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, Media);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Media).call(this));
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        var selectors = new Selector([], null, null, _this._index, _this._fileInfo).createEmptySelectors();
        _this.features = new Value(features);
        _this.rules = [new Ruleset(selectors, value)];
        _this.rules[0].allowImports = true;
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        _this.allowRoot = true;
  
        _this.setParent(selectors, _assertThisInitialized(_this));
  
        _this.setParent(_this.features, _assertThisInitialized(_this));
  
        _this.setParent(_this.rules, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(Media, [{
        key: "isRulesetLike",
        value: function isRulesetLike() {
          return true;
        }
      }, {
        key: "accept",
        value: function accept(visitor) {
          if (this.features) {
            this.features = visitor.visit(this.features);
          }
  
          if (this.rules) {
            this.rules = visitor.visitArray(this.rules);
          }
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add('@media ', this._fileInfo, this._index);
          this.features.genCSS(context, output);
          this.outputRuleset(context, output, this.rules);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          if (!context.mediaBlocks) {
            context.mediaBlocks = [];
            context.mediaPath = [];
          }
  
          var media = new Media(null, [], this._index, this._fileInfo, this.visibilityInfo());
  
          if (this.debugInfo) {
            this.rules[0].debugInfo = this.debugInfo;
            media.debugInfo = this.debugInfo;
          }
  
          media.features = this.features.eval(context);
          context.mediaPath.push(media);
          context.mediaBlocks.push(media);
          this.rules[0].functionRegistry = context.frames[0].functionRegistry.inherit();
          context.frames.unshift(this.rules[0]);
          media.rules = [this.rules[0].eval(context)];
          context.frames.shift();
          context.mediaPath.pop();
          return context.mediaPath.length === 0 ? media.evalTop(context) : media.evalNested(context);
        }
      }, {
        key: "evalTop",
        value: function evalTop(context) {
          var result = this; // Render all dependent Media blocks.
  
          if (context.mediaBlocks.length > 1) {
            var selectors = new Selector([], null, null, this.getIndex(), this.fileInfo()).createEmptySelectors();
            result = new Ruleset(selectors, context.mediaBlocks);
            result.multiMedia = true;
            result.copyVisibilityInfo(this.visibilityInfo());
            this.setParent(result, this);
          }
  
          delete context.mediaBlocks;
          delete context.mediaPath;
          return result;
        }
      }, {
        key: "evalNested",
        value: function evalNested(context) {
          var i;
          var value;
          var path = context.mediaPath.concat([this]); // Extract the media-query conditions separated with `,` (OR).
  
          for (i = 0; i < path.length; i++) {
            value = path[i].features instanceof Value ? path[i].features.value : path[i].features;
            path[i] = Array.isArray(value) ? value : [value];
          } // Trace all permutations to generate the resulting media-query.
          //
          // (a, b and c) with nested (d, e) ->
          //    a and d
          //    a and e
          //    b and c and d
          //    b and c and e
  
  
          this.features = new Value(this.permute(path).map(function (path) {
            path = path.map(function (fragment) {
              return fragment.toCSS ? fragment : new Anonymous(fragment);
            });
  
            for (i = path.length - 1; i > 0; i--) {
              path.splice(i, 0, new Anonymous('and'));
            }
  
            return new Expression(path);
          }));
          this.setParent(this.features, this); // Fake a tree-node that doesn't output anything.
  
          return new Ruleset([], []);
        }
      }, {
        key: "permute",
        value: function permute(arr) {
          if (arr.length === 0) {
            return [];
          } else if (arr.length === 1) {
            return arr[0];
          } else {
            var result = [];
            var rest = this.permute(arr.slice(1));
  
            for (var i = 0; i < rest.length; i++) {
              for (var j = 0; j < arr[0].length; j++) {
                result.push([arr[0][j]].concat(rest[i]));
              }
            }
  
            return result;
          }
        }
      }, {
        key: "bubbleSelectors",
        value: function bubbleSelectors(selectors) {
          if (!selectors) {
            return;
          }
  
          this.rules = [new Ruleset(copyArray(selectors), [this.rules[0]])];
          this.setParent(this.rules, this);
        }
      }]);
  
      return Media;
    }(AtRule);
  
    Media.prototype.type = 'Media';
  
    // CSS @import node
    //
    // The general strategy here is that we don't want to wait
    // for the parsing to be completed, before we start importing
    // the file. That's because in the context of a browser,
    // most of the time will be spent waiting for the server to respond.
    //
    // On creation, we push the import path to our import queue, though
    // `import,push`, we also pass it a callback, which it'll call once
    // the file has been fetched, and parsed.
    //
  
    var Import =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Import, _Node);
  
      function Import(path, features, options, index, currentFileInfo, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, Import);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Import).call(this));
        _this.options = options;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.path = path;
        _this.features = features;
        _this.allowRoot = true;
  
        if (_this.options.less !== undefined || _this.options.inline) {
          _this.css = !_this.options.less || _this.options.inline;
        } else {
          var pathValue = _this.getPath();
  
          if (pathValue && /[#\.\&\?]css([\?;].*)?$/.test(pathValue)) {
            _this.css = true;
          }
        }
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        _this.setParent(_this.features, _assertThisInitialized(_this));
  
        _this.setParent(_this.path, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(Import, [{
        key: "accept",
        value: function accept(visitor) {
          if (this.features) {
            this.features = visitor.visit(this.features);
          }
  
          this.path = visitor.visit(this.path);
  
          if (!this.options.isPlugin && !this.options.inline && this.root) {
            this.root = visitor.visit(this.root);
          }
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          if (this.css && this.path._fileInfo.reference === undefined) {
            output.add('@import ', this._fileInfo, this._index);
            this.path.genCSS(context, output);
  
            if (this.features) {
              output.add(' ');
              this.features.genCSS(context, output);
            }
  
            output.add(';');
          }
        }
      }, {
        key: "getPath",
        value: function getPath() {
          return this.path instanceof URL ? this.path.value.value : this.path.value;
        }
      }, {
        key: "isVariableImport",
        value: function isVariableImport() {
          var path = this.path;
  
          if (path instanceof URL) {
            path = path.value;
          }
  
          if (path instanceof Quoted) {
            return path.containsVariables();
          }
  
          return true;
        }
      }, {
        key: "evalForImport",
        value: function evalForImport(context) {
          var path = this.path;
  
          if (path instanceof URL) {
            path = path.value;
          }
  
          return new Import(path.eval(context), this.features, this.options, this._index, this._fileInfo, this.visibilityInfo());
        }
      }, {
        key: "evalPath",
        value: function evalPath(context) {
          var path = this.path.eval(context);
          var fileInfo = this._fileInfo;
  
          if (!(path instanceof URL)) {
            // Add the rootpath if the URL requires a rewrite
            var pathValue = path.value;
  
            if (fileInfo && pathValue && context.pathRequiresRewrite(pathValue)) {
              path.value = context.rewritePath(pathValue, fileInfo.rootpath);
            } else {
              path.value = context.normalizePath(path.value);
            }
          }
  
          return path;
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var result = this.doEval(context);
  
          if (this.options.reference || this.blocksVisibility()) {
            if (result.length || result.length === 0) {
              result.forEach(function (node) {
                node.addVisibilityBlock();
              });
            } else {
              result.addVisibilityBlock();
            }
          }
  
          return result;
        }
      }, {
        key: "doEval",
        value: function doEval(context) {
          var ruleset;
          var registry;
          var features = this.features && this.features.eval(context);
  
          if (this.options.isPlugin) {
            if (this.root && this.root.eval) {
              try {
                this.root.eval(context);
              } catch (e) {
                e.message = 'Plugin error during evaluation';
                throw new LessError(e, this.root.imports, this.root.filename);
              }
            }
  
            registry = context.frames[0] && context.frames[0].functionRegistry;
  
            if (registry && this.root && this.root.functions) {
              registry.addMultiple(this.root.functions);
            }
  
            return [];
          }
  
          if (this.skip) {
            if (typeof this.skip === 'function') {
              this.skip = this.skip();
            }
  
            if (this.skip) {
              return [];
            }
          }
  
          if (this.options.inline) {
            var contents = new Anonymous(this.root, 0, {
              filename: this.importedFilename,
              reference: this.path._fileInfo && this.path._fileInfo.reference
            }, true, true);
            return this.features ? new Media([contents], this.features.value) : [contents];
          } else if (this.css) {
            var newImport = new Import(this.evalPath(context), features, this.options, this._index);
  
            if (!newImport.css && this.error) {
              throw this.error;
            }
  
            return newImport;
          } else {
            ruleset = new Ruleset(null, copyArray(this.root.rules));
            ruleset.evalImports(context);
            return this.features ? new Media(ruleset.rules, this.features.value) : ruleset.rules;
          }
        }
      }]);
  
      return Import;
    }(Node);
  
    Import.prototype.type = 'Import';
  
    var JsEvalNode =
    /*#__PURE__*/
    function (_Node) {
      _inherits(JsEvalNode, _Node);
  
      function JsEvalNode() {
        _classCallCheck(this, JsEvalNode);
  
        return _possibleConstructorReturn(this, _getPrototypeOf(JsEvalNode).apply(this, arguments));
      }
  
      _createClass(JsEvalNode, [{
        key: "evaluateJavaScript",
        value: function evaluateJavaScript(expression, context) {
          var result;
          var that = this;
          var evalContext = {};
  
          if (!context.javascriptEnabled) {
            throw {
              message: 'Inline JavaScript is not enabled. Is it set in your options?',
              filename: this.fileInfo().filename,
              index: this.getIndex()
            };
          }
  
          expression = expression.replace(/@\{([\w-]+)\}/g, function (_, name) {
            return that.jsify(new Variable("@".concat(name), that.getIndex(), that.fileInfo()).eval(context));
          });
  
          try {
            expression = new Function("return (".concat(expression, ")"));
          } catch (e) {
            throw {
              message: "JavaScript evaluation error: ".concat(e.message, " from `").concat(expression, "`"),
              filename: this.fileInfo().filename,
              index: this.getIndex()
            };
          }
  
          var variables = context.frames[0].variables();
  
          for (var k in variables) {
            if (variables.hasOwnProperty(k)) {
              /* jshint loopfunc:true */
              evalContext[k.slice(1)] = {
                value: variables[k].value,
                toJS: function toJS() {
                  return this.value.eval(context).toCSS();
                }
              };
            }
          }
  
          try {
            result = expression.call(evalContext);
          } catch (e) {
            throw {
              message: "JavaScript evaluation error: '".concat(e.name, ": ").concat(e.message.replace(/["]/g, '\''), "'"),
              filename: this.fileInfo().filename,
              index: this.getIndex()
            };
          }
  
          return result;
        }
      }, {
        key: "jsify",
        value: function jsify(obj) {
          if (Array.isArray(obj.value) && obj.value.length > 1) {
            return "[".concat(obj.value.map(function (v) {
              return v.toCSS();
            }).join(', '), "]");
          } else {
            return obj.toCSS();
          }
        }
      }]);
  
      return JsEvalNode;
    }(Node);
  
    var JavaScript =
    /*#__PURE__*/
    function (_JsEvalNode) {
      _inherits(JavaScript, _JsEvalNode);
  
      function JavaScript(string, escaped, index, currentFileInfo) {
        var _this;
  
        _classCallCheck(this, JavaScript);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(JavaScript).call(this));
        _this.escaped = escaped;
        _this.expression = string;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        return _this;
      }
  
      _createClass(JavaScript, [{
        key: "eval",
        value: function _eval(context) {
          var result = this.evaluateJavaScript(this.expression, context);
  
          var type = _typeof(result);
  
          if (type === 'number' && !isNaN(result)) {
            return new Dimension(result);
          } else if (type === 'string') {
            return new Quoted("\"".concat(result, "\""), result, this.escaped, this._index);
          } else if (Array.isArray(result)) {
            return new Anonymous(result.join(', '));
          } else {
            return new Anonymous(result);
          }
        }
      }]);
  
      return JavaScript;
    }(JsEvalNode);
  
    JavaScript.prototype.type = 'JavaScript';
  
    var Assignment =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Assignment, _Node);
  
      function Assignment(key, val) {
        var _this;
  
        _classCallCheck(this, Assignment);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Assignment).call(this));
        _this.key = key;
        _this.value = val;
        return _this;
      }
  
      _createClass(Assignment, [{
        key: "accept",
        value: function accept(visitor) {
          this.value = visitor.visit(this.value);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          if (this.value.eval) {
            return new Assignment(this.key, this.value.eval(context));
          }
  
          return this;
        }
      }, {
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add("".concat(this.key, "="));
  
          if (this.value.genCSS) {
            this.value.genCSS(context, output);
          } else {
            output.add(this.value);
          }
        }
      }]);
  
      return Assignment;
    }(Node);
  
    Assignment.prototype.type = 'Assignment';
  
    var Condition =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Condition, _Node);
  
      function Condition(op, l, r, i, negate) {
        var _this;
  
        _classCallCheck(this, Condition);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Condition).call(this));
        _this.op = op.trim();
        _this.lvalue = l;
        _this.rvalue = r;
        _this._index = i;
        _this.negate = negate;
        return _this;
      }
  
      _createClass(Condition, [{
        key: "accept",
        value: function accept(visitor) {
          this.lvalue = visitor.visit(this.lvalue);
          this.rvalue = visitor.visit(this.rvalue);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var result = function (op, a, b) {
            switch (op) {
              case 'and':
                return a && b;
  
              case 'or':
                return a || b;
  
              default:
                switch (Node.compare(a, b)) {
                  case -1:
                    return op === '<' || op === '=<' || op === '<=';
  
                  case 0:
                    return op === '=' || op === '>=' || op === '=<' || op === '<=';
  
                  case 1:
                    return op === '>' || op === '>=';
  
                  default:
                    return false;
                }
  
            }
          }(this.op, this.lvalue.eval(context), this.rvalue.eval(context));
  
          return this.negate ? !result : result;
        }
      }]);
  
      return Condition;
    }(Node);
  
    Condition.prototype.type = 'Condition';
  
    var UnicodeDescriptor =
    /*#__PURE__*/
    function (_Node) {
      _inherits(UnicodeDescriptor, _Node);
  
      function UnicodeDescriptor(value) {
        var _this;
  
        _classCallCheck(this, UnicodeDescriptor);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(UnicodeDescriptor).call(this));
        _this.value = value;
        return _this;
      }
  
      return UnicodeDescriptor;
    }(Node);
  
    UnicodeDescriptor.prototype.type = 'UnicodeDescriptor';
  
    var Negative =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Negative, _Node);
  
      function Negative(node) {
        var _this;
  
        _classCallCheck(this, Negative);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Negative).call(this));
        _this.value = node;
        return _this;
      }
  
      _createClass(Negative, [{
        key: "genCSS",
        value: function genCSS(context, output) {
          output.add('-');
          this.value.genCSS(context, output);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          if (context.isMathOn()) {
            return new Operation('*', [new Dimension(-1), this.value]).eval(context);
          }
  
          return new Negative(this.value.eval(context));
        }
      }]);
  
      return Negative;
    }(Node);
  
    Negative.prototype.type = 'Negative';
  
    var Extend =
    /*#__PURE__*/
    function (_Node) {
      _inherits(Extend, _Node);
  
      function Extend(selector, option, index, currentFileInfo, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, Extend);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Extend).call(this));
        _this.selector = selector;
        _this.option = option;
        _this.object_id = Extend.next_id++;
        _this.parent_ids = [_this.object_id];
        _this._index = index;
        _this._fileInfo = currentFileInfo;
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        _this.allowRoot = true;
  
        switch (option) {
          case 'all':
            _this.allowBefore = true;
            _this.allowAfter = true;
            break;
  
          default:
            _this.allowBefore = false;
            _this.allowAfter = false;
            break;
        }
  
        _this.setParent(_this.selector, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(Extend, [{
        key: "accept",
        value: function accept(visitor) {
          this.selector = visitor.visit(this.selector);
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          return new Extend(this.selector.eval(context), this.option, this.getIndex(), this.fileInfo(), this.visibilityInfo());
        }
      }, {
        key: "clone",
        value: function clone(context) {
          return new Extend(this.selector, this.option, this.getIndex(), this.fileInfo(), this.visibilityInfo());
        } // it concatenates (joins) all selectors in selector array
  
      }, {
        key: "findSelfSelectors",
        value: function findSelfSelectors(selectors) {
          var selfElements = [];
          var i;
          var selectorElements;
  
          for (i = 0; i < selectors.length; i++) {
            selectorElements = selectors[i].elements; // duplicate the logic in genCSS function inside the selector node.
            // future TODO - move both logics into the selector joiner visitor
  
            if (i > 0 && selectorElements.length && selectorElements[0].combinator.value === '') {
              selectorElements[0].combinator.value = ' ';
            }
  
            selfElements = selfElements.concat(selectors[i].elements);
          }
  
          this.selfSelectors = [new Selector(selfElements)];
          this.selfSelectors[0].copyVisibilityInfo(this.visibilityInfo());
        }
      }]);
  
      return Extend;
    }(Node);
  
    Extend.next_id = 0;
    Extend.prototype.type = 'Extend';
  
    var VariableCall =
    /*#__PURE__*/
    function (_Node) {
      _inherits(VariableCall, _Node);
  
      function VariableCall(variable, index, currentFileInfo) {
        var _this;
  
        _classCallCheck(this, VariableCall);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(VariableCall).call(this));
        _this.variable = variable;
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.allowRoot = true;
        return _this;
      }
  
      _createClass(VariableCall, [{
        key: "eval",
        value: function _eval(context) {
          var rules;
          var detachedRuleset = new Variable(this.variable, this.getIndex(), this.fileInfo()).eval(context);
          var error = new LessError({
            message: "Could not evaluate variable call ".concat(this.variable)
          });
  
          if (!detachedRuleset.ruleset) {
            if (detachedRuleset.rules) {
              rules = detachedRuleset;
            } else if (Array.isArray(detachedRuleset)) {
              rules = new Ruleset('', detachedRuleset);
            } else if (Array.isArray(detachedRuleset.value)) {
              rules = new Ruleset('', detachedRuleset.value);
            } else {
              throw error;
            }
  
            detachedRuleset = new DetachedRuleset(rules);
          }
  
          if (detachedRuleset.ruleset) {
            return detachedRuleset.callEval(context);
          }
  
          throw error;
        }
      }]);
  
      return VariableCall;
    }(Node);
  
    VariableCall.prototype.type = 'VariableCall';
  
    var NamespaceValue =
    /*#__PURE__*/
    function (_Node) {
      _inherits(NamespaceValue, _Node);
  
      function NamespaceValue(ruleCall, lookups, important, index, fileInfo) {
        var _this;
  
        _classCallCheck(this, NamespaceValue);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(NamespaceValue).call(this));
        _this.value = ruleCall;
        _this.lookups = lookups;
        _this.important = important;
        _this._index = index;
        _this._fileInfo = fileInfo;
        return _this;
      }
  
      _createClass(NamespaceValue, [{
        key: "eval",
        value: function _eval(context) {
          var i;
          var name;
          var rules = this.value.eval(context);
  
          for (i = 0; i < this.lookups.length; i++) {
            name = this.lookups[i];
            /**
             * Eval'd DRs return rulesets.
             * Eval'd mixins return rules, so let's make a ruleset if we need it.
             * We need to do this because of late parsing of values
             */
  
            if (Array.isArray(rules)) {
              rules = new Ruleset([new Selector()], rules);
            }
  
            if (name === '') {
              rules = rules.lastDeclaration();
            } else if (name.charAt(0) === '@') {
              if (name.charAt(1) === '@') {
                name = "@".concat(new Variable(name.substr(1)).eval(context).value);
              }
  
              if (rules.variables) {
                rules = rules.variable(name);
              }
  
              if (!rules) {
                throw {
                  type: 'Name',
                  message: "variable ".concat(name, " not found"),
                  filename: this.fileInfo().filename,
                  index: this.getIndex()
                };
              }
            } else {
              if (name.substring(0, 2) === '$@') {
                name = "$".concat(new Variable(name.substr(1)).eval(context).value);
              } else {
                name = name.charAt(0) === '$' ? name : "$".concat(name);
              }
  
              if (rules.properties) {
                rules = rules.property(name);
              }
  
              if (!rules) {
                throw {
                  type: 'Name',
                  message: "property \"".concat(name.substr(1), "\" not found"),
                  filename: this.fileInfo().filename,
                  index: this.getIndex()
                };
              } // Properties are an array of values, since a ruleset can have multiple props.
              // We pick the last one (the "cascaded" value)
  
  
              rules = rules[rules.length - 1];
            }
  
            if (rules.value) {
              rules = rules.eval(context).value;
            }
  
            if (rules.ruleset) {
              rules = rules.ruleset.eval(context);
            }
          }
  
          return rules;
        }
      }]);
  
      return NamespaceValue;
    }(Node);
  
    NamespaceValue.prototype.type = 'NamespaceValue';
  
    var Definition =
    /*#__PURE__*/
    function (_Ruleset) {
      _inherits(Definition, _Ruleset);
  
      function Definition(name, params, rules, condition, variadic, frames, visibilityInfo) {
        var _this;
  
        _classCallCheck(this, Definition);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(Definition).call(this));
        _this.name = name || 'anonymous mixin';
        _this.selectors = [new Selector([new Element(null, name, false, _this._index, _this._fileInfo)])];
        _this.params = params;
        _this.condition = condition;
        _this.variadic = variadic;
        _this.arity = params.length;
        _this.rules = rules;
        _this._lookups = {};
        var optionalParameters = [];
        _this.required = params.reduce(function (count, p) {
          if (!p.name || p.name && !p.value) {
            return count + 1;
          } else {
            optionalParameters.push(p.name);
            return count;
          }
        }, 0);
        _this.optionalParameters = optionalParameters;
        _this.frames = frames;
  
        _this.copyVisibilityInfo(visibilityInfo);
  
        _this.allowRoot = true;
        return _this;
      }
  
      _createClass(Definition, [{
        key: "accept",
        value: function accept(visitor) {
          if (this.params && this.params.length) {
            this.params = visitor.visitArray(this.params);
          }
  
          this.rules = visitor.visitArray(this.rules);
  
          if (this.condition) {
            this.condition = visitor.visit(this.condition);
          }
        }
      }, {
        key: "evalParams",
        value: function evalParams(context, mixinEnv, args, evaldArguments) {
          /* jshint boss:true */
          var frame = new Ruleset(null, null);
          var varargs;
          var arg;
          var params = copyArray(this.params);
          var i;
          var j;
          var val;
          var name;
          var isNamedFound;
          var argIndex;
          var argsLength = 0;
  
          if (mixinEnv.frames && mixinEnv.frames[0] && mixinEnv.frames[0].functionRegistry) {
            frame.functionRegistry = mixinEnv.frames[0].functionRegistry.inherit();
          }
  
          mixinEnv = new contexts.Eval(mixinEnv, [frame].concat(mixinEnv.frames));
  
          if (args) {
            args = copyArray(args);
            argsLength = args.length;
  
            for (i = 0; i < argsLength; i++) {
              arg = args[i];
  
              if (name = arg && arg.name) {
                isNamedFound = false;
  
                for (j = 0; j < params.length; j++) {
                  if (!evaldArguments[j] && name === params[j].name) {
                    evaldArguments[j] = arg.value.eval(context);
                    frame.prependRule(new Declaration(name, arg.value.eval(context)));
                    isNamedFound = true;
                    break;
                  }
                }
  
                if (isNamedFound) {
                  args.splice(i, 1);
                  i--;
                  continue;
                } else {
                  throw {
                    type: 'Runtime',
                    message: "Named argument for ".concat(this.name, " ").concat(args[i].name, " not found")
                  };
                }
              }
            }
          }
  
          argIndex = 0;
  
          for (i = 0; i < params.length; i++) {
            if (evaldArguments[i]) {
              continue;
            }
  
            arg = args && args[argIndex];
  
            if (name = params[i].name) {
              if (params[i].variadic) {
                varargs = [];
  
                for (j = argIndex; j < argsLength; j++) {
                  varargs.push(args[j].value.eval(context));
                }
  
                frame.prependRule(new Declaration(name, new Expression(varargs).eval(context)));
              } else {
                val = arg && arg.value;
  
                if (val) {
                  // This was a mixin call, pass in a detached ruleset of it's eval'd rules
                  if (Array.isArray(val)) {
                    val = new DetachedRuleset(new Ruleset('', val));
                  } else {
                    val = val.eval(context);
                  }
                } else if (params[i].value) {
                  val = params[i].value.eval(mixinEnv);
                  frame.resetCache();
                } else {
                  throw {
                    type: 'Runtime',
                    message: "wrong number of arguments for ".concat(this.name, " (").concat(argsLength, " for ").concat(this.arity, ")")
                  };
                }
  
                frame.prependRule(new Declaration(name, val));
                evaldArguments[i] = val;
              }
            }
  
            if (params[i].variadic && args) {
              for (j = argIndex; j < argsLength; j++) {
                evaldArguments[j] = args[j].value.eval(context);
              }
            }
  
            argIndex++;
          }
  
          return frame;
        }
      }, {
        key: "makeImportant",
        value: function makeImportant() {
          var rules = !this.rules ? this.rules : this.rules.map(function (r) {
            if (r.makeImportant) {
              return r.makeImportant(true);
            } else {
              return r;
            }
          });
          var result = new Definition(this.name, this.params, rules, this.condition, this.variadic, this.frames);
          return result;
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          return new Definition(this.name, this.params, this.rules, this.condition, this.variadic, this.frames || copyArray(context.frames));
        }
      }, {
        key: "evalCall",
        value: function evalCall(context, args, important) {
          var _arguments = [];
          var mixinFrames = this.frames ? this.frames.concat(context.frames) : context.frames;
          var frame = this.evalParams(context, new contexts.Eval(context, mixinFrames), args, _arguments);
          var rules;
          var ruleset;
          frame.prependRule(new Declaration('@arguments', new Expression(_arguments).eval(context)));
          rules = copyArray(this.rules);
          ruleset = new Ruleset(null, rules);
          ruleset.originalRuleset = this;
          ruleset = ruleset.eval(new contexts.Eval(context, [this, frame].concat(mixinFrames)));
  
          if (important) {
            ruleset = ruleset.makeImportant();
          }
  
          return ruleset;
        }
      }, {
        key: "matchCondition",
        value: function matchCondition(args, context) {
          if (this.condition && !this.condition.eval(new contexts.Eval(context, [this.evalParams(context,
          /* the parameter variables */
          new contexts.Eval(context, this.frames ? this.frames.concat(context.frames) : context.frames), args, [])].concat(this.frames || []) // the parent namespace/mixin frames
          .concat(context.frames)))) {
            // the current environment frames
            return false;
          }
  
          return true;
        }
      }, {
        key: "matchArgs",
        value: function matchArgs(args, context) {
          var allArgsCnt = args && args.length || 0;
          var len;
          var optionalParameters = this.optionalParameters;
          var requiredArgsCnt = !args ? 0 : args.reduce(function (count, p) {
            if (optionalParameters.indexOf(p.name) < 0) {
              return count + 1;
            } else {
              return count;
            }
          }, 0);
  
          if (!this.variadic) {
            if (requiredArgsCnt < this.required) {
              return false;
            }
  
            if (allArgsCnt > this.params.length) {
              return false;
            }
          } else {
            if (requiredArgsCnt < this.required - 1) {
              return false;
            }
          } // check patterns
  
  
          len = Math.min(requiredArgsCnt, this.arity);
  
          for (var i = 0; i < len; i++) {
            if (!this.params[i].name && !this.params[i].variadic) {
              if (args[i].value.eval(context).toCSS() != this.params[i].value.eval(context).toCSS()) {
                return false;
              }
            }
          }
  
          return true;
        }
      }]);
  
      return Definition;
    }(Ruleset);
  
    Definition.prototype.type = 'MixinDefinition';
    Definition.prototype.evalFirst = true;
  
    var MixinCall =
    /*#__PURE__*/
    function (_Node) {
      _inherits(MixinCall, _Node);
  
      function MixinCall(elements, args, index, currentFileInfo, important) {
        var _this;
  
        _classCallCheck(this, MixinCall);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(MixinCall).call(this));
        _this.selector = new Selector(elements);
        _this.arguments = args || [];
        _this._index = index;
        _this._fileInfo = currentFileInfo;
        _this.important = important;
        _this.allowRoot = true;
  
        _this.setParent(_this.selector, _assertThisInitialized(_this));
  
        return _this;
      }
  
      _createClass(MixinCall, [{
        key: "accept",
        value: function accept(visitor) {
          if (this.selector) {
            this.selector = visitor.visit(this.selector);
          }
  
          if (this.arguments.length) {
            this.arguments = visitor.visitArray(this.arguments);
          }
        }
      }, {
        key: "eval",
        value: function _eval(context) {
          var mixins;
          var mixin;
          var mixinPath;
          var args = [];
          var arg;
          var argValue;
          var rules = [];
          var match = false;
          var i;
          var m;
          var f;
          var isRecursive;
          var isOneFound;
          var candidates = [];
          var candidate;
          var conditionResult = [];
          var defaultResult;
          var defFalseEitherCase = -1;
          var defNone = 0;
          var defTrue = 1;
          var defFalse = 2;
          var count;
          var originalRuleset;
          var noArgumentsFilter;
          this.selector = this.selector.eval(context);
  
          function calcDefGroup(mixin, mixinPath) {
            var f;
            var p;
            var namespace;
  
            for (f = 0; f < 2; f++) {
              conditionResult[f] = true;
              defaultFunc.value(f);
  
              for (p = 0; p < mixinPath.length && conditionResult[f]; p++) {
                namespace = mixinPath[p];
  
                if (namespace.matchCondition) {
                  conditionResult[f] = conditionResult[f] && namespace.matchCondition(null, context);
                }
              }
  
              if (mixin.matchCondition) {
                conditionResult[f] = conditionResult[f] && mixin.matchCondition(args, context);
              }
            }
  
            if (conditionResult[0] || conditionResult[1]) {
              if (conditionResult[0] != conditionResult[1]) {
                return conditionResult[1] ? defTrue : defFalse;
              }
  
              return defNone;
            }
  
            return defFalseEitherCase;
          }
  
          for (i = 0; i < this.arguments.length; i++) {
            arg = this.arguments[i];
            argValue = arg.value.eval(context);
  
            if (arg.expand && Array.isArray(argValue.value)) {
              argValue = argValue.value;
  
              for (m = 0; m < argValue.length; m++) {
                args.push({
                  value: argValue[m]
                });
              }
            } else {
              args.push({
                name: arg.name,
                value: argValue
              });
            }
          }
  
          noArgumentsFilter = function noArgumentsFilter(rule) {
            return rule.matchArgs(null, context);
          };
  
          for (i = 0; i < context.frames.length; i++) {
            if ((mixins = context.frames[i].find(this.selector, null, noArgumentsFilter)).length > 0) {
              isOneFound = true; // To make `default()` function independent of definition order we have two "subpasses" here.
              // At first we evaluate each guard *twice* (with `default() == true` and `default() == false`),
              // and build candidate list with corresponding flags. Then, when we know all possible matches,
              // we make a final decision.
  
              for (m = 0; m < mixins.length; m++) {
                mixin = mixins[m].rule;
                mixinPath = mixins[m].path;
                isRecursive = false;
  
                for (f = 0; f < context.frames.length; f++) {
                  if (!(mixin instanceof Definition) && mixin === (context.frames[f].originalRuleset || context.frames[f])) {
                    isRecursive = true;
                    break;
                  }
                }
  
                if (isRecursive) {
                  continue;
                }
  
                if (mixin.matchArgs(args, context)) {
                  candidate = {
                    mixin: mixin,
                    group: calcDefGroup(mixin, mixinPath)
                  };
  
                  if (candidate.group !== defFalseEitherCase) {
                    candidates.push(candidate);
                  }
  
                  match = true;
                }
              }
  
              defaultFunc.reset();
              count = [0, 0, 0];
  
              for (m = 0; m < candidates.length; m++) {
                count[candidates[m].group]++;
              }
  
              if (count[defNone] > 0) {
                defaultResult = defFalse;
              } else {
                defaultResult = defTrue;
  
                if (count[defTrue] + count[defFalse] > 1) {
                  throw {
                    type: 'Runtime',
                    message: "Ambiguous use of `default()` found when matching for `".concat(this.format(args), "`"),
                    index: this.getIndex(),
                    filename: this.fileInfo().filename
                  };
                }
              }
  
              for (m = 0; m < candidates.length; m++) {
                candidate = candidates[m].group;
  
                if (candidate === defNone || candidate === defaultResult) {
                  try {
                    mixin = candidates[m].mixin;
  
                    if (!(mixin instanceof Definition)) {
                      originalRuleset = mixin.originalRuleset || mixin;
                      mixin = new Definition('', [], mixin.rules, null, false, null, originalRuleset.visibilityInfo());
                      mixin.originalRuleset = originalRuleset;
                    }
  
                    var newRules = mixin.evalCall(context, args, this.important).rules;
  
                    this._setVisibilityToReplacement(newRules);
  
                    Array.prototype.push.apply(rules, newRules);
                  } catch (e) {
                    throw {
                      message: e.message,
                      index: this.getIndex(),
                      filename: this.fileInfo().filename,
                      stack: e.stack
                    };
                  }
                }
              }
  
              if (match) {
                return rules;
              }
            }
          }
  
          if (isOneFound) {
            throw {
              type: 'Runtime',
              message: "No matching definition was found for `".concat(this.format(args), "`"),
              index: this.getIndex(),
              filename: this.fileInfo().filename
            };
          } else {
            throw {
              type: 'Name',
              message: "".concat(this.selector.toCSS().trim(), " is undefined"),
              index: this.getIndex(),
              filename: this.fileInfo().filename
            };
          }
        }
      }, {
        key: "_setVisibilityToReplacement",
        value: function _setVisibilityToReplacement(replacement) {
          var i;
          var rule;
  
          if (this.blocksVisibility()) {
            for (i = 0; i < replacement.length; i++) {
              rule = replacement[i];
              rule.addVisibilityBlock();
            }
          }
        }
      }, {
        key: "format",
        value: function format(args) {
          return "".concat(this.selector.toCSS().trim(), "(").concat(args ? args.map(function (a) {
            var argValue = '';
  
            if (a.name) {
              argValue += "".concat(a.name, ":");
            }
  
            if (a.value.toCSS) {
              argValue += a.value.toCSS();
            } else {
              argValue += '???';
            }
  
            return argValue;
          }).join(', ') : '', ")");
        }
      }]);
  
      return MixinCall;
    }(Node);
  
    MixinCall.prototype.type = 'MixinCall';
  
    var tree = {
      Node: Node,
      Color: Color,
      AtRule: AtRule,
      DetachedRuleset: DetachedRuleset,
      Operation: Operation,
      Dimension: Dimension,
      Unit: Unit,
      Keyword: Keyword,
      Variable: Variable,
      Property: Property,
      Ruleset: Ruleset,
      Element: Element,
      Attribute: Attribute,
      Combinator: Combinator,
      Selector: Selector,
      Quoted: Quoted,
      Expression: Expression,
      Declaration: Declaration,
      Call: Call,
      URL: URL,
      Import: Import,
      Comment: Comment,
      Anonymous: Anonymous,
      Value: Value,
      JavaScript: JavaScript,
      Assignment: Assignment,
      Condition: Condition,
      Paren: Paren,
      Media: Media,
      UnicodeDescriptor: UnicodeDescriptor,
      Negative: Negative,
      Extend: Extend,
      VariableCall: VariableCall,
      NamespaceValue: NamespaceValue,
      mixin: {
        Call: MixinCall,
        Definition: Definition
      }
    };
  
    var logger = {
      error: function error(msg) {
        this._fireEvent('error', msg);
      },
      warn: function warn(msg) {
        this._fireEvent('warn', msg);
      },
      info: function info(msg) {
        this._fireEvent('info', msg);
      },
      debug: function debug(msg) {
        this._fireEvent('debug', msg);
      },
      addListener: function addListener(listener) {
        this._listeners.push(listener);
      },
      removeListener: function removeListener(listener) {
        for (var i = 0; i < this._listeners.length; i++) {
          if (this._listeners[i] === listener) {
            this._listeners.splice(i, 1);
  
            return;
          }
        }
      },
      _fireEvent: function _fireEvent(type, msg) {
        for (var i = 0; i < this._listeners.length; i++) {
          var logFunction = this._listeners[i][type];
  
          if (logFunction) {
            logFunction(msg);
          }
        }
      },
      _listeners: []
    };
  
    var environment =
    /*#__PURE__*/
    function () {
      function environment(externalEnvironment, fileManagers) {
        _classCallCheck(this, environment);
  
        this.fileManagers = fileManagers || [];
        externalEnvironment = externalEnvironment || {};
        var optionalFunctions = ['encodeBase64', 'mimeLookup', 'charsetLookup', 'getSourceMapGenerator'];
        var requiredFunctions = [];
        var functions = requiredFunctions.concat(optionalFunctions);
  
        for (var i = 0; i < functions.length; i++) {
          var propName = functions[i];
          var environmentFunc = externalEnvironment[propName];
  
          if (environmentFunc) {
            this[propName] = environmentFunc.bind(externalEnvironment);
          } else if (i < requiredFunctions.length) {
            this.warn("missing required function in environment - ".concat(propName));
          }
        }
      }
  
      _createClass(environment, [{
        key: "getFileManager",
        value: function getFileManager(filename, currentDirectory, options, environment, isSync) {
          if (!filename) {
            logger.warn('getFileManager called with no filename.. Please report this issue. continuing.');
          }
  
          if (currentDirectory == null) {
            logger.warn('getFileManager called with null directory.. Please report this issue. continuing.');
          }
  
          var fileManagers = this.fileManagers;
  
          if (options.pluginManager) {
            fileManagers = [].concat(fileManagers).concat(options.pluginManager.getFileManagers());
          }
  
          for (var i = fileManagers.length - 1; i >= 0; i--) {
            var fileManager = fileManagers[i];
  
            if (fileManager[isSync ? 'supportsSync' : 'supports'](filename, currentDirectory, options, environment)) {
              return fileManager;
            }
          }
  
          return null;
        }
      }, {
        key: "addFileManager",
        value: function addFileManager(fileManager) {
          this.fileManagers.push(fileManager);
        }
      }, {
        key: "clearFileManagers",
        value: function clearFileManagers() {
          this.fileManagers = [];
        }
      }]);
  
      return environment;
    }();
  
    var AbstractFileManager =
    /*#__PURE__*/
    function () {
      function AbstractFileManager() {
        _classCallCheck(this, AbstractFileManager);
      }
  
      _createClass(AbstractFileManager, [{
        key: "getPath",
        value: function getPath(filename) {
          var j = filename.lastIndexOf('?');
  
          if (j > 0) {
            filename = filename.slice(0, j);
          }
  
          j = filename.lastIndexOf('/');
  
          if (j < 0) {
            j = filename.lastIndexOf('\\');
          }
  
          if (j < 0) {
            return '';
          }
  
          return filename.slice(0, j + 1);
        }
      }, {
        key: "tryAppendExtension",
        value: function tryAppendExtension(path, ext) {
          return /(\.[a-z]*$)|([\?;].*)$/.test(path) ? path : path + ext;
        }
      }, {
        key: "tryAppendLessExtension",
        value: function tryAppendLessExtension(path) {
          return this.tryAppendExtension(path, '.less');
        }
      }, {
        key: "supportsSync",
        value: function supportsSync() {
          return false;
        }
      }, {
        key: "alwaysMakePathsAbsolute",
        value: function alwaysMakePathsAbsolute() {
          return false;
        }
      }, {
        key: "isPathAbsolute",
        value: function isPathAbsolute(filename) {
          return /^(?:[a-z-]+:|\/|\\|#)/i.test(filename);
        } // TODO: pull out / replace?
  
      }, {
        key: "join",
        value: function join(basePath, laterPath) {
          if (!basePath) {
            return laterPath;
          }
  
          return basePath + laterPath;
        }
      }, {
        key: "pathDiff",
        value: function pathDiff(url, baseUrl) {
          // diff between two paths to create a relative path
          var urlParts = this.extractUrlParts(url);
          var baseUrlParts = this.extractUrlParts(baseUrl);
          var i;
          var max;
          var urlDirectories;
          var baseUrlDirectories;
          var diff = '';
  
          if (urlParts.hostPart !== baseUrlParts.hostPart) {
            return '';
          }
  
          max = Math.max(baseUrlParts.directories.length, urlParts.directories.length);
  
          for (i = 0; i < max; i++) {
            if (baseUrlParts.directories[i] !== urlParts.directories[i]) {
              break;
            }
          }
  
          baseUrlDirectories = baseUrlParts.directories.slice(i);
          urlDirectories = urlParts.directories.slice(i);
  
          for (i = 0; i < baseUrlDirectories.length - 1; i++) {
            diff += '../';
          }
  
          for (i = 0; i < urlDirectories.length - 1; i++) {
            diff += "".concat(urlDirectories[i], "/");
          }
  
          return diff;
        }
      }, {
        key: "extractUrlParts",
        // helper function, not part of API
        value: function extractUrlParts(url, baseUrl) {
          // urlParts[1] = protocol://hostname/ OR /
          // urlParts[2] = / if path relative to host base
          // urlParts[3] = directories
          // urlParts[4] = filename
          // urlParts[5] = parameters
          var urlPartsRegex = /^((?:[a-z-]+:)?\/{2}(?:[^\/\?#]*\/)|([\/\\]))?((?:[^\/\\\?#]*[\/\\])*)([^\/\\\?#]*)([#\?].*)?$/i;
          var urlParts = url.match(urlPartsRegex);
          var returner = {};
          var rawDirectories = [];
          var directories = [];
          var i;
          var baseUrlParts;
  
          if (!urlParts) {
            throw new Error("Could not parse sheet href - '".concat(url, "'"));
          } // Stylesheets in IE don't always return the full path
  
  
          if (baseUrl && (!urlParts[1] || urlParts[2])) {
            baseUrlParts = baseUrl.match(urlPartsRegex);
  
            if (!baseUrlParts) {
              throw new Error("Could not parse page url - '".concat(baseUrl, "'"));
            }
  
            urlParts[1] = urlParts[1] || baseUrlParts[1] || '';
  
            if (!urlParts[2]) {
              urlParts[3] = baseUrlParts[3] + urlParts[3];
            }
          }
  
          if (urlParts[3]) {
            rawDirectories = urlParts[3].replace(/\\/g, '/').split('/'); // collapse '..' and skip '.'
  
            for (i = 0; i < rawDirectories.length; i++) {
              if (rawDirectories[i] === '..') {
                directories.pop();
              } else if (rawDirectories[i] !== '.') {
                directories.push(rawDirectories[i]);
              }
            }
          }
  
          returner.hostPart = urlParts[1];
          returner.directories = directories;
          returner.rawPath = (urlParts[1] || '') + rawDirectories.join('/');
          returner.path = (urlParts[1] || '') + directories.join('/');
          returner.filename = urlParts[4];
          returner.fileUrl = returner.path + (urlParts[4] || '');
          returner.url = returner.fileUrl + (urlParts[5] || '');
          return returner;
        }
      }]);
  
      return AbstractFileManager;
    }();
  
    var AbstractPluginLoader =
    /*#__PURE__*/
    function () {
      function AbstractPluginLoader() {
        _classCallCheck(this, AbstractPluginLoader);
  
        // Implemented by Node.js plugin loader
        this.require = function () {
          return null;
        };
      }
  
      _createClass(AbstractPluginLoader, [{
        key: "evalPlugin",
        value: function evalPlugin(contents, context, imports, pluginOptions, fileInfo) {
          var loader;
          var registry;
          var pluginObj;
          var localModule;
          var pluginManager;
          var filename;
          var result;
          pluginManager = context.pluginManager;
  
          if (fileInfo) {
            if (typeof fileInfo === 'string') {
              filename = fileInfo;
            } else {
              filename = fileInfo.filename;
            }
          }
  
          var shortname = new this.less.FileManager().extractUrlParts(filename).filename;
  
          if (filename) {
            pluginObj = pluginManager.get(filename);
  
            if (pluginObj) {
              result = this.trySetOptions(pluginObj, filename, shortname, pluginOptions);
  
              if (result) {
                return result;
              }
  
              try {
                if (pluginObj.use) {
                  pluginObj.use.call(this.context, pluginObj);
                }
              } catch (e) {
                e.message = e.message || 'Error during @plugin call';
                return new LessError(e, imports, filename);
              }
  
              return pluginObj;
            }
          }
  
          localModule = {
            exports: {},
            pluginManager: pluginManager,
            fileInfo: fileInfo
          };
          registry = functionRegistry.create();
  
          var registerPlugin = function registerPlugin(obj) {
            pluginObj = obj;
          };
  
          try {
            loader = new Function('module', 'require', 'registerPlugin', 'functions', 'tree', 'less', 'fileInfo', contents);
            loader(localModule, this.require(filename), registerPlugin, registry, this.less.tree, this.less, fileInfo);
          } catch (e) {
            return new LessError(e, imports, filename);
          }
  
          if (!pluginObj) {
            pluginObj = localModule.exports;
          }
  
          pluginObj = this.validatePlugin(pluginObj, filename, shortname);
  
          if (pluginObj instanceof LessError) {
            return pluginObj;
          }
  
          if (pluginObj) {
            pluginObj.imports = imports;
            pluginObj.filename = filename; // For < 3.x (or unspecified minVersion) - setOptions() before install()
  
            if (!pluginObj.minVersion || this.compareVersion('3.0.0', pluginObj.minVersion) < 0) {
              result = this.trySetOptions(pluginObj, filename, shortname, pluginOptions);
  
              if (result) {
                return result;
              }
            } // Run on first load
  
  
            pluginManager.addPlugin(pluginObj, fileInfo.filename, registry);
            pluginObj.functions = registry.getLocalFunctions(); // Need to call setOptions again because the pluginObj might have functions
  
            result = this.trySetOptions(pluginObj, filename, shortname, pluginOptions);
  
            if (result) {
              return result;
            } // Run every @plugin call
  
  
            try {
              if (pluginObj.use) {
                pluginObj.use.call(this.context, pluginObj);
              }
            } catch (e) {
              e.message = e.message || 'Error during @plugin call';
              return new LessError(e, imports, filename);
            }
          } else {
            return new LessError({
              message: 'Not a valid plugin'
            }, imports, filename);
          }
  
          return pluginObj;
        }
      }, {
        key: "trySetOptions",
        value: function trySetOptions(plugin, filename, name, options) {
          if (options && !plugin.setOptions) {
            return new LessError({
              message: "Options have been provided but the plugin ".concat(name, " does not support any options.")
            });
          }
  
          try {
            plugin.setOptions && plugin.setOptions(options);
          } catch (e) {
            return new LessError(e);
          }
        }
      }, {
        key: "validatePlugin",
        value: function validatePlugin(plugin, filename, name) {
          if (plugin) {
            // support plugins being a function
            // so that the plugin can be more usable programmatically
            if (typeof plugin === 'function') {
              plugin = new plugin();
            }
  
            if (plugin.minVersion) {
              if (this.compareVersion(plugin.minVersion, this.less.version) < 0) {
                return new LessError({
                  message: "Plugin ".concat(name, " requires version ").concat(this.versionToString(plugin.minVersion))
                });
              }
            }
  
            return plugin;
          }
  
          return null;
        }
      }, {
        key: "compareVersion",
        value: function compareVersion(aVersion, bVersion) {
          if (typeof aVersion === 'string') {
            aVersion = aVersion.match(/^(\d+)\.?(\d+)?\.?(\d+)?/);
            aVersion.shift();
          }
  
          for (var i = 0; i < aVersion.length; i++) {
            if (aVersion[i] !== bVersion[i]) {
              return parseInt(aVersion[i]) > parseInt(bVersion[i]) ? -1 : 1;
            }
          }
  
          return 0;
        }
      }, {
        key: "versionToString",
        value: function versionToString(version) {
          var versionString = '';
  
          for (var i = 0; i < version.length; i++) {
            versionString += (versionString ? '.' : '') + version[i];
          }
  
          return versionString;
        }
      }, {
        key: "printUsage",
        value: function printUsage(plugins) {
          for (var i = 0; i < plugins.length; i++) {
            var plugin = plugins[i];
  
            if (plugin.printUsage) {
              plugin.printUsage();
            }
          }
        }
      }]);
  
      return AbstractPluginLoader;
    }();
  
    var _visitArgs = {
      visitDeeper: true
    };
    var _hasIndexed = false;
  
    function _noop(node) {
      return node;
    }
  
    function indexNodeTypes(parent, ticker) {
      // add .typeIndex to tree node types for lookup table
      var key;
      var child;
  
      for (key in parent) {
        /* eslint guard-for-in: 0 */
        child = parent[key];
  
        switch (_typeof(child)) {
          case 'function':
            // ignore bound functions directly on tree which do not have a prototype
            // or aren't nodes
            if (child.prototype && child.prototype.type) {
              child.prototype.typeIndex = ticker++;
            }
  
            break;
  
          case 'object':
            ticker = indexNodeTypes(child, ticker);
            break;
        }
      }
  
      return ticker;
    }
  
    var Visitor =
    /*#__PURE__*/
    function () {
      function Visitor(implementation) {
        _classCallCheck(this, Visitor);
  
        this._implementation = implementation;
        this._visitInCache = {};
        this._visitOutCache = {};
  
        if (!_hasIndexed) {
          indexNodeTypes(tree, 1);
          _hasIndexed = true;
        }
      }
  
      _createClass(Visitor, [{
        key: "visit",
        value: function visit(node) {
          if (!node) {
            return node;
          }
  
          var nodeTypeIndex = node.typeIndex;
  
          if (!nodeTypeIndex) {
            // MixinCall args aren't a node type?
            if (node.value && node.value.typeIndex) {
              this.visit(node.value);
            }
  
            return node;
          }
  
          var impl = this._implementation;
          var func = this._visitInCache[nodeTypeIndex];
          var funcOut = this._visitOutCache[nodeTypeIndex];
          var visitArgs = _visitArgs;
          var fnName;
          visitArgs.visitDeeper = true;
  
          if (!func) {
            fnName = "visit".concat(node.type);
            func = impl[fnName] || _noop;
            funcOut = impl["".concat(fnName, "Out")] || _noop;
            this._visitInCache[nodeTypeIndex] = func;
            this._visitOutCache[nodeTypeIndex] = funcOut;
          }
  
          if (func !== _noop) {
            var newNode = func.call(impl, node, visitArgs);
  
            if (node && impl.isReplacing) {
              node = newNode;
            }
          }
  
          if (visitArgs.visitDeeper && node && node.accept) {
            node.accept(this);
          }
  
          if (funcOut != _noop) {
            funcOut.call(impl, node);
          }
  
          return node;
        }
      }, {
        key: "visitArray",
        value: function visitArray(nodes, nonReplacing) {
          if (!nodes) {
            return nodes;
          }
  
          var cnt = nodes.length;
          var i; // Non-replacing
  
          if (nonReplacing || !this._implementation.isReplacing) {
            for (i = 0; i < cnt; i++) {
              this.visit(nodes[i]);
            }
  
            return nodes;
          } // Replacing
  
  
          var out = [];
  
          for (i = 0; i < cnt; i++) {
            var evald = this.visit(nodes[i]);
  
            if (evald === undefined) {
              continue;
            }
  
            if (!evald.splice) {
              out.push(evald);
            } else if (evald.length) {
              this.flatten(evald, out);
            }
          }
  
          return out;
        }
      }, {
        key: "flatten",
        value: function flatten(arr, out) {
          if (!out) {
            out = [];
          }
  
          var cnt;
          var i;
          var item;
          var nestedCnt;
          var j;
          var nestedItem;
  
          for (i = 0, cnt = arr.length; i < cnt; i++) {
            item = arr[i];
  
            if (item === undefined) {
              continue;
            }
  
            if (!item.splice) {
              out.push(item);
              continue;
            }
  
            for (j = 0, nestedCnt = item.length; j < nestedCnt; j++) {
              nestedItem = item[j];
  
              if (nestedItem === undefined) {
                continue;
              }
  
              if (!nestedItem.splice) {
                out.push(nestedItem);
              } else if (nestedItem.length) {
                this.flatten(nestedItem, out);
              }
            }
          }
  
          return out;
        }
      }]);
  
      return Visitor;
    }();
  
    var ImportSequencer =
    /*#__PURE__*/
    function () {
      function ImportSequencer(onSequencerEmpty) {
        _classCallCheck(this, ImportSequencer);
  
        this.imports = [];
        this.variableImports = [];
        this._onSequencerEmpty = onSequencerEmpty;
        this._currentDepth = 0;
      }
  
      _createClass(ImportSequencer, [{
        key: "addImport",
        value: function addImport(callback) {
          var importSequencer = this;
          var importItem = {
            callback: callback,
            args: null,
            isReady: false
          };
          this.imports.push(importItem);
          return function () {
            for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
              args[_key] = arguments[_key];
            }
  
            importItem.args = Array.prototype.slice.call(args, 0);
            importItem.isReady = true;
            importSequencer.tryRun();
          };
        }
      }, {
        key: "addVariableImport",
        value: function addVariableImport(callback) {
          this.variableImports.push(callback);
        }
      }, {
        key: "tryRun",
        value: function tryRun() {
          this._currentDepth++;
  
          try {
            while (true) {
              while (this.imports.length > 0) {
                var importItem = this.imports[0];
  
                if (!importItem.isReady) {
                  return;
                }
  
                this.imports = this.imports.slice(1);
                importItem.callback.apply(null, importItem.args);
              }
  
              if (this.variableImports.length === 0) {
                break;
              }
  
              var variableImport = this.variableImports[0];
              this.variableImports = this.variableImports.slice(1);
              variableImport();
            }
          } finally {
            this._currentDepth--;
          }
  
          if (this._currentDepth === 0 && this._onSequencerEmpty) {
            this._onSequencerEmpty();
          }
        }
      }]);
  
      return ImportSequencer;
    }();
  
    var ImportVisitor = function ImportVisitor(importer, finish) {
      this._visitor = new Visitor(this);
      this._importer = importer;
      this._finish = finish;
      this.context = new contexts.Eval();
      this.importCount = 0;
      this.onceFileDetectionMap = {};
      this.recursionDetector = {};
      this._sequencer = new ImportSequencer(this._onSequencerEmpty.bind(this));
    };
  
    ImportVisitor.prototype = {
      isReplacing: false,
      run: function run(root) {
        try {
          // process the contents
          this._visitor.visit(root);
        } catch (e) {
          this.error = e;
        }
  
        this.isFinished = true;
  
        this._sequencer.tryRun();
      },
      _onSequencerEmpty: function _onSequencerEmpty() {
        if (!this.isFinished) {
          return;
        }
  
        this._finish(this.error);
      },
      visitImport: function visitImport(importNode, visitArgs) {
        var inlineCSS = importNode.options.inline;
  
        if (!importNode.css || inlineCSS) {
          var context = new contexts.Eval(this.context, copyArray(this.context.frames));
          var importParent = context.frames[0];
          this.importCount++;
  
          if (importNode.isVariableImport()) {
            this._sequencer.addVariableImport(this.processImportNode.bind(this, importNode, context, importParent));
          } else {
            this.processImportNode(importNode, context, importParent);
          }
        }
  
        visitArgs.visitDeeper = false;
      },
      processImportNode: function processImportNode(importNode, context, importParent) {
        var evaldImportNode;
        var inlineCSS = importNode.options.inline;
  
        try {
          evaldImportNode = importNode.evalForImport(context);
        } catch (e) {
          if (!e.filename) {
            e.index = importNode.getIndex();
            e.filename = importNode.fileInfo().filename;
          } // attempt to eval properly and treat as css
  
  
          importNode.css = true; // if that fails, this error will be thrown
  
          importNode.error = e;
        }
  
        if (evaldImportNode && (!evaldImportNode.css || inlineCSS)) {
          if (evaldImportNode.options.multiple) {
            context.importMultiple = true;
          } // try appending if we haven't determined if it is css or not
  
  
          var tryAppendLessExtension = evaldImportNode.css === undefined;
  
          for (var i = 0; i < importParent.rules.length; i++) {
            if (importParent.rules[i] === importNode) {
              importParent.rules[i] = evaldImportNode;
              break;
            }
          }
  
          var onImported = this.onImported.bind(this, evaldImportNode, context);
  
          var sequencedOnImported = this._sequencer.addImport(onImported);
  
          this._importer.push(evaldImportNode.getPath(), tryAppendLessExtension, evaldImportNode.fileInfo(), evaldImportNode.options, sequencedOnImported);
        } else {
          this.importCount--;
  
          if (this.isFinished) {
            this._sequencer.tryRun();
          }
        }
      },
      onImported: function onImported(importNode, context, e, root, importedAtRoot, fullPath) {
        if (e) {
          if (!e.filename) {
            e.index = importNode.getIndex();
            e.filename = importNode.fileInfo().filename;
          }
  
          this.error = e;
        }
  
        var importVisitor = this;
        var inlineCSS = importNode.options.inline;
        var isPlugin = importNode.options.isPlugin;
        var isOptional = importNode.options.optional;
        var duplicateImport = importedAtRoot || fullPath in importVisitor.recursionDetector;
  
        if (!context.importMultiple) {
          if (duplicateImport) {
            importNode.skip = true;
          } else {
            importNode.skip = function () {
              if (fullPath in importVisitor.onceFileDetectionMap) {
                return true;
              }
  
              importVisitor.onceFileDetectionMap[fullPath] = true;
              return false;
            };
          }
        }
  
        if (!fullPath && isOptional) {
          importNode.skip = true;
        }
  
        if (root) {
          importNode.root = root;
          importNode.importedFilename = fullPath;
  
          if (!inlineCSS && !isPlugin && (context.importMultiple || !duplicateImport)) {
            importVisitor.recursionDetector[fullPath] = true;
            var oldContext = this.context;
            this.context = context;
  
            try {
              this._visitor.visit(root);
            } catch (e) {
              this.error = e;
            }
  
            this.context = oldContext;
          }
        }
  
        importVisitor.importCount--;
  
        if (importVisitor.isFinished) {
          importVisitor._sequencer.tryRun();
        }
      },
      visitDeclaration: function visitDeclaration(declNode, visitArgs) {
        if (declNode.value.type === 'DetachedRuleset') {
          this.context.frames.unshift(declNode);
        } else {
          visitArgs.visitDeeper = false;
        }
      },
      visitDeclarationOut: function visitDeclarationOut(declNode) {
        if (declNode.value.type === 'DetachedRuleset') {
          this.context.frames.shift();
        }
      },
      visitAtRule: function visitAtRule(atRuleNode, visitArgs) {
        this.context.frames.unshift(atRuleNode);
      },
      visitAtRuleOut: function visitAtRuleOut(atRuleNode) {
        this.context.frames.shift();
      },
      visitMixinDefinition: function visitMixinDefinition(mixinDefinitionNode, visitArgs) {
        this.context.frames.unshift(mixinDefinitionNode);
      },
      visitMixinDefinitionOut: function visitMixinDefinitionOut(mixinDefinitionNode) {
        this.context.frames.shift();
      },
      visitRuleset: function visitRuleset(rulesetNode, visitArgs) {
        this.context.frames.unshift(rulesetNode);
      },
      visitRulesetOut: function visitRulesetOut(rulesetNode) {
        this.context.frames.shift();
      },
      visitMedia: function visitMedia(mediaNode, visitArgs) {
        this.context.frames.unshift(mediaNode.rules[0]);
      },
      visitMediaOut: function visitMediaOut(mediaNode) {
        this.context.frames.shift();
      }
    };
  
    var SetTreeVisibilityVisitor =
    /*#__PURE__*/
    function () {
      function SetTreeVisibilityVisitor(visible) {
        _classCallCheck(this, SetTreeVisibilityVisitor);
  
        this.visible = visible;
      }
  
      _createClass(SetTreeVisibilityVisitor, [{
        key: "run",
        value: function run(root) {
          this.visit(root);
        }
      }, {
        key: "visitArray",
        value: function visitArray(nodes) {
          if (!nodes) {
            return nodes;
          }
  
          var cnt = nodes.length;
          var i;
  
          for (i = 0; i < cnt; i++) {
            this.visit(nodes[i]);
          }
  
          return nodes;
        }
      }, {
        key: "visit",
        value: function visit(node) {
          if (!node) {
            return node;
          }
  
          if (node.constructor === Array) {
            return this.visitArray(node);
          }
  
          if (!node.blocksVisibility || node.blocksVisibility()) {
            return node;
          }
  
          if (this.visible) {
            node.ensureVisibility();
          } else {
            node.ensureInvisibility();
          }
  
          node.accept(this);
          return node;
        }
      }]);
  
      return SetTreeVisibilityVisitor;
    }();
  
    /* jshint loopfunc:true */
  
    var ExtendFinderVisitor =
    /*#__PURE__*/
    function () {
      function ExtendFinderVisitor() {
        _classCallCheck(this, ExtendFinderVisitor);
  
        this._visitor = new Visitor(this);
        this.contexts = [];
        this.allExtendsStack = [[]];
      }
  
      _createClass(ExtendFinderVisitor, [{
        key: "run",
        value: function run(root) {
          root = this._visitor.visit(root);
          root.allExtends = this.allExtendsStack[0];
          return root;
        }
      }, {
        key: "visitDeclaration",
        value: function visitDeclaration(declNode, visitArgs) {
          visitArgs.visitDeeper = false;
        }
      }, {
        key: "visitMixinDefinition",
        value: function visitMixinDefinition(mixinDefinitionNode, visitArgs) {
          visitArgs.visitDeeper = false;
        }
      }, {
        key: "visitRuleset",
        value: function visitRuleset(rulesetNode, visitArgs) {
          if (rulesetNode.root) {
            return;
          }
  
          var i;
          var j;
          var extend;
          var allSelectorsExtendList = [];
          var extendList; // get &:extend(.a); rules which apply to all selectors in this ruleset
  
          var rules = rulesetNode.rules;
          var ruleCnt = rules ? rules.length : 0;
  
          for (i = 0; i < ruleCnt; i++) {
            if (rulesetNode.rules[i] instanceof tree.Extend) {
              allSelectorsExtendList.push(rules[i]);
              rulesetNode.extendOnEveryPath = true;
            }
          } // now find every selector and apply the extends that apply to all extends
          // and the ones which apply to an individual extend
  
  
          var paths = rulesetNode.paths;
  
          for (i = 0; i < paths.length; i++) {
            var selectorPath = paths[i];
            var selector = selectorPath[selectorPath.length - 1];
            var selExtendList = selector.extendList;
            extendList = selExtendList ? copyArray(selExtendList).concat(allSelectorsExtendList) : allSelectorsExtendList;
  
            if (extendList) {
              extendList = extendList.map(function (allSelectorsExtend) {
                return allSelectorsExtend.clone();
              });
            }
  
            for (j = 0; j < extendList.length; j++) {
              this.foundExtends = true;
              extend = extendList[j];
              extend.findSelfSelectors(selectorPath);
              extend.ruleset = rulesetNode;
  
              if (j === 0) {
                extend.firstExtendOnThisSelectorPath = true;
              }
  
              this.allExtendsStack[this.allExtendsStack.length - 1].push(extend);
            }
          }
  
          this.contexts.push(rulesetNode.selectors);
        }
      }, {
        key: "visitRulesetOut",
        value: function visitRulesetOut(rulesetNode) {
          if (!rulesetNode.root) {
            this.contexts.length = this.contexts.length - 1;
          }
        }
      }, {
        key: "visitMedia",
        value: function visitMedia(mediaNode, visitArgs) {
          mediaNode.allExtends = [];
          this.allExtendsStack.push(mediaNode.allExtends);
        }
      }, {
        key: "visitMediaOut",
        value: function visitMediaOut(mediaNode) {
          this.allExtendsStack.length = this.allExtendsStack.length - 1;
        }
      }, {
        key: "visitAtRule",
        value: function visitAtRule(atRuleNode, visitArgs) {
          atRuleNode.allExtends = [];
          this.allExtendsStack.push(atRuleNode.allExtends);
        }
      }, {
        key: "visitAtRuleOut",
        value: function visitAtRuleOut(atRuleNode) {
          this.allExtendsStack.length = this.allExtendsStack.length - 1;
        }
      }]);
  
      return ExtendFinderVisitor;
    }();
  
    var ProcessExtendsVisitor =
    /*#__PURE__*/
    function () {
      function ProcessExtendsVisitor() {
        _classCallCheck(this, ProcessExtendsVisitor);
  
        this._visitor = new Visitor(this);
      }
  
      _createClass(ProcessExtendsVisitor, [{
        key: "run",
        value: function run(root) {
          var extendFinder = new ExtendFinderVisitor();
          this.extendIndices = {};
          extendFinder.run(root);
  
          if (!extendFinder.foundExtends) {
            return root;
          }
  
          root.allExtends = root.allExtends.concat(this.doExtendChaining(root.allExtends, root.allExtends));
          this.allExtendsStack = [root.allExtends];
  
          var newRoot = this._visitor.visit(root);
  
          this.checkExtendsForNonMatched(root.allExtends);
          return newRoot;
        }
      }, {
        key: "checkExtendsForNonMatched",
        value: function checkExtendsForNonMatched(extendList) {
          var indices = this.extendIndices;
          extendList.filter(function (extend) {
            return !extend.hasFoundMatches && extend.parent_ids.length == 1;
          }).forEach(function (extend) {
            var selector = '_unknown_';
  
            try {
              selector = extend.selector.toCSS({});
            } catch (_) {}
  
            if (!indices["".concat(extend.index, " ").concat(selector)]) {
              indices["".concat(extend.index, " ").concat(selector)] = true;
              logger.warn("extend '".concat(selector, "' has no matches"));
            }
          });
        }
      }, {
        key: "doExtendChaining",
        value: function doExtendChaining(extendsList, extendsListTarget, iterationCount) {
          //
          // chaining is different from normal extension.. if we extend an extend then we are not just copying, altering
          // and pasting the selector we would do normally, but we are also adding an extend with the same target selector
          // this means this new extend can then go and alter other extends
          //
          // this method deals with all the chaining work - without it, extend is flat and doesn't work on other extend selectors
          // this is also the most expensive.. and a match on one selector can cause an extension of a selector we had already
          // processed if we look at each selector at a time, as is done in visitRuleset
          var extendIndex;
          var targetExtendIndex;
          var matches;
          var extendsToAdd = [];
          var newSelector;
          var extendVisitor = this;
          var selectorPath;
          var extend;
          var targetExtend;
          var newExtend;
          iterationCount = iterationCount || 0; // loop through comparing every extend with every target extend.
          // a target extend is the one on the ruleset we are looking at copy/edit/pasting in place
          // e.g.  .a:extend(.b) {}  and .b:extend(.c) {} then the first extend extends the second one
          // and the second is the target.
          // the separation into two lists allows us to process a subset of chains with a bigger set, as is the
          // case when processing media queries
  
          for (extendIndex = 0; extendIndex < extendsList.length; extendIndex++) {
            for (targetExtendIndex = 0; targetExtendIndex < extendsListTarget.length; targetExtendIndex++) {
              extend = extendsList[extendIndex];
              targetExtend = extendsListTarget[targetExtendIndex]; // look for circular references
  
              if (extend.parent_ids.indexOf(targetExtend.object_id) >= 0) {
                continue;
              } // find a match in the target extends self selector (the bit before :extend)
  
  
              selectorPath = [targetExtend.selfSelectors[0]];
              matches = extendVisitor.findMatch(extend, selectorPath);
  
              if (matches.length) {
                extend.hasFoundMatches = true; // we found a match, so for each self selector..
  
                extend.selfSelectors.forEach(function (selfSelector) {
                  var info = targetExtend.visibilityInfo(); // process the extend as usual
  
                  newSelector = extendVisitor.extendSelector(matches, selectorPath, selfSelector, extend.isVisible()); // but now we create a new extend from it
  
                  newExtend = new tree.Extend(targetExtend.selector, targetExtend.option, 0, targetExtend.fileInfo(), info);
                  newExtend.selfSelectors = newSelector; // add the extend onto the list of extends for that selector
  
                  newSelector[newSelector.length - 1].extendList = [newExtend]; // record that we need to add it.
  
                  extendsToAdd.push(newExtend);
                  newExtend.ruleset = targetExtend.ruleset; // remember its parents for circular references
  
                  newExtend.parent_ids = newExtend.parent_ids.concat(targetExtend.parent_ids, extend.parent_ids); // only process the selector once.. if we have :extend(.a,.b) then multiple
                  // extends will look at the same selector path, so when extending
                  // we know that any others will be duplicates in terms of what is added to the css
  
                  if (targetExtend.firstExtendOnThisSelectorPath) {
                    newExtend.firstExtendOnThisSelectorPath = true;
                    targetExtend.ruleset.paths.push(newSelector);
                  }
                });
              }
            }
          }
  
          if (extendsToAdd.length) {
            // try to detect circular references to stop a stack overflow.
            // may no longer be needed.
            this.extendChainCount++;
  
            if (iterationCount > 100) {
              var selectorOne = '{unable to calculate}';
              var selectorTwo = '{unable to calculate}';
  
              try {
                selectorOne = extendsToAdd[0].selfSelectors[0].toCSS();
                selectorTwo = extendsToAdd[0].selector.toCSS();
              } catch (e) {}
  
              throw {
                message: "extend circular reference detected. One of the circular extends is currently:".concat(selectorOne, ":extend(").concat(selectorTwo, ")")
              };
            } // now process the new extends on the existing rules so that we can handle a extending b extending c extending
            // d extending e...
  
  
            return extendsToAdd.concat(extendVisitor.doExtendChaining(extendsToAdd, extendsListTarget, iterationCount + 1));
          } else {
            return extendsToAdd;
          }
        }
      }, {
        key: "visitDeclaration",
        value: function visitDeclaration(ruleNode, visitArgs) {
          visitArgs.visitDeeper = false;
        }
      }, {
        key: "visitMixinDefinition",
        value: function visitMixinDefinition(mixinDefinitionNode, visitArgs) {
          visitArgs.visitDeeper = false;
        }
      }, {
        key: "visitSelector",
        value: function visitSelector(selectorNode, visitArgs) {
          visitArgs.visitDeeper = false;
        }
      }, {
        key: "visitRuleset",
        value: function visitRuleset(rulesetNode, visitArgs) {
          if (rulesetNode.root) {
            return;
          }
  
          var matches;
          var pathIndex;
          var extendIndex;
          var allExtends = this.allExtendsStack[this.allExtendsStack.length - 1];
          var selectorsToAdd = [];
          var extendVisitor = this;
          var selectorPath; // look at each selector path in the ruleset, find any extend matches and then copy, find and replace
  
          for (extendIndex = 0; extendIndex < allExtends.length; extendIndex++) {
            for (pathIndex = 0; pathIndex < rulesetNode.paths.length; pathIndex++) {
              selectorPath = rulesetNode.paths[pathIndex]; // extending extends happens initially, before the main pass
  
              if (rulesetNode.extendOnEveryPath) {
                continue;
              }
  
              var extendList = selectorPath[selectorPath.length - 1].extendList;
  
              if (extendList && extendList.length) {
                continue;
              }
  
              matches = this.findMatch(allExtends[extendIndex], selectorPath);
  
              if (matches.length) {
                allExtends[extendIndex].hasFoundMatches = true;
                allExtends[extendIndex].selfSelectors.forEach(function (selfSelector) {
                  var extendedSelectors;
                  extendedSelectors = extendVisitor.extendSelector(matches, selectorPath, selfSelector, allExtends[extendIndex].isVisible());
                  selectorsToAdd.push(extendedSelectors);
                });
              }
            }
          }
  
          rulesetNode.paths = rulesetNode.paths.concat(selectorsToAdd);
        }
      }, {
        key: "findMatch",
        value: function findMatch(extend, haystackSelectorPath) {
          //
          // look through the haystack selector path to try and find the needle - extend.selector
          // returns an array of selector matches that can then be replaced
          //
          var haystackSelectorIndex;
          var hackstackSelector;
          var hackstackElementIndex;
          var haystackElement;
          var targetCombinator;
          var i;
          var extendVisitor = this;
          var needleElements = extend.selector.elements;
          var potentialMatches = [];
          var potentialMatch;
          var matches = []; // loop through the haystack elements
  
          for (haystackSelectorIndex = 0; haystackSelectorIndex < haystackSelectorPath.length; haystackSelectorIndex++) {
            hackstackSelector = haystackSelectorPath[haystackSelectorIndex];
  
            for (hackstackElementIndex = 0; hackstackElementIndex < hackstackSelector.elements.length; hackstackElementIndex++) {
              haystackElement = hackstackSelector.elements[hackstackElementIndex]; // if we allow elements before our match we can add a potential match every time. otherwise only at the first element.
  
              if (extend.allowBefore || haystackSelectorIndex === 0 && hackstackElementIndex === 0) {
                potentialMatches.push({
                  pathIndex: haystackSelectorIndex,
                  index: hackstackElementIndex,
                  matched: 0,
                  initialCombinator: haystackElement.combinator
                });
              }
  
              for (i = 0; i < potentialMatches.length; i++) {
                potentialMatch = potentialMatches[i]; // selectors add " " onto the first element. When we use & it joins the selectors together, but if we don't
                // then each selector in haystackSelectorPath has a space before it added in the toCSS phase. so we need to
                // work out what the resulting combinator will be
  
                targetCombinator = haystackElement.combinator.value;
  
                if (targetCombinator === '' && hackstackElementIndex === 0) {
                  targetCombinator = ' ';
                } // if we don't match, null our match to indicate failure
  
  
                if (!extendVisitor.isElementValuesEqual(needleElements[potentialMatch.matched].value, haystackElement.value) || potentialMatch.matched > 0 && needleElements[potentialMatch.matched].combinator.value !== targetCombinator) {
                  potentialMatch = null;
                } else {
                  potentialMatch.matched++;
                } // if we are still valid and have finished, test whether we have elements after and whether these are allowed
  
  
                if (potentialMatch) {
                  potentialMatch.finished = potentialMatch.matched === needleElements.length;
  
                  if (potentialMatch.finished && !extend.allowAfter && (hackstackElementIndex + 1 < hackstackSelector.elements.length || haystackSelectorIndex + 1 < haystackSelectorPath.length)) {
                    potentialMatch = null;
                  }
                } // if null we remove, if not, we are still valid, so either push as a valid match or continue
  
  
                if (potentialMatch) {
                  if (potentialMatch.finished) {
                    potentialMatch.length = needleElements.length;
                    potentialMatch.endPathIndex = haystackSelectorIndex;
                    potentialMatch.endPathElementIndex = hackstackElementIndex + 1; // index after end of match
  
                    potentialMatches.length = 0; // we don't allow matches to overlap, so start matching again
  
                    matches.push(potentialMatch);
                  }
                } else {
                  potentialMatches.splice(i, 1);
                  i--;
                }
              }
            }
          }
  
          return matches;
        }
      }, {
        key: "isElementValuesEqual",
        value: function isElementValuesEqual(elementValue1, elementValue2) {
          if (typeof elementValue1 === 'string' || typeof elementValue2 === 'string') {
            return elementValue1 === elementValue2;
          }
  
          if (elementValue1 instanceof tree.Attribute) {
            if (elementValue1.op !== elementValue2.op || elementValue1.key !== elementValue2.key) {
              return false;
            }
  
            if (!elementValue1.value || !elementValue2.value) {
              if (elementValue1.value || elementValue2.value) {
                return false;
              }
  
              return true;
            }
  
            elementValue1 = elementValue1.value.value || elementValue1.value;
            elementValue2 = elementValue2.value.value || elementValue2.value;
            return elementValue1 === elementValue2;
          }
  
          elementValue1 = elementValue1.value;
          elementValue2 = elementValue2.value;
  
          if (elementValue1 instanceof tree.Selector) {
            if (!(elementValue2 instanceof tree.Selector) || elementValue1.elements.length !== elementValue2.elements.length) {
              return false;
            }
  
            for (var i = 0; i < elementValue1.elements.length; i++) {
              if (elementValue1.elements[i].combinator.value !== elementValue2.elements[i].combinator.value) {
                if (i !== 0 || (elementValue1.elements[i].combinator.value || ' ') !== (elementValue2.elements[i].combinator.value || ' ')) {
                  return false;
                }
              }
  
              if (!this.isElementValuesEqual(elementValue1.elements[i].value, elementValue2.elements[i].value)) {
                return false;
              }
            }
  
            return true;
          }
  
          return false;
        }
      }, {
        key: "extendSelector",
        value: function extendSelector(matches, selectorPath, replacementSelector, isVisible) {
          // for a set of matches, replace each match with the replacement selector
          var currentSelectorPathIndex = 0;
          var currentSelectorPathElementIndex = 0;
          var path = [];
          var matchIndex;
          var selector;
          var firstElement;
          var match;
          var newElements;
  
          for (matchIndex = 0; matchIndex < matches.length; matchIndex++) {
            match = matches[matchIndex];
            selector = selectorPath[match.pathIndex];
            firstElement = new tree.Element(match.initialCombinator, replacementSelector.elements[0].value, replacementSelector.elements[0].isVariable, replacementSelector.elements[0].getIndex(), replacementSelector.elements[0].fileInfo());
  
            if (match.pathIndex > currentSelectorPathIndex && currentSelectorPathElementIndex > 0) {
              path[path.length - 1].elements = path[path.length - 1].elements.concat(selectorPath[currentSelectorPathIndex].elements.slice(currentSelectorPathElementIndex));
              currentSelectorPathElementIndex = 0;
              currentSelectorPathIndex++;
            }
  
            newElements = selector.elements.slice(currentSelectorPathElementIndex, match.index).concat([firstElement]).concat(replacementSelector.elements.slice(1));
  
            if (currentSelectorPathIndex === match.pathIndex && matchIndex > 0) {
              path[path.length - 1].elements = path[path.length - 1].elements.concat(newElements);
            } else {
              path = path.concat(selectorPath.slice(currentSelectorPathIndex, match.pathIndex));
              path.push(new tree.Selector(newElements));
            }
  
            currentSelectorPathIndex = match.endPathIndex;
            currentSelectorPathElementIndex = match.endPathElementIndex;
  
            if (currentSelectorPathElementIndex >= selectorPath[currentSelectorPathIndex].elements.length) {
              currentSelectorPathElementIndex = 0;
              currentSelectorPathIndex++;
            }
          }
  
          if (currentSelectorPathIndex < selectorPath.length && currentSelectorPathElementIndex > 0) {
            path[path.length - 1].elements = path[path.length - 1].elements.concat(selectorPath[currentSelectorPathIndex].elements.slice(currentSelectorPathElementIndex));
            currentSelectorPathIndex++;
          }
  
          path = path.concat(selectorPath.slice(currentSelectorPathIndex, selectorPath.length));
          path = path.map(function (currentValue) {
            // we can re-use elements here, because the visibility property matters only for selectors
            var derived = currentValue.createDerived(currentValue.elements);
  
            if (isVisible) {
              derived.ensureVisibility();
            } else {
              derived.ensureInvisibility();
            }
  
            return derived;
          });
          return path;
        }
      }, {
        key: "visitMedia",
        value: function visitMedia(mediaNode, visitArgs) {
          var newAllExtends = mediaNode.allExtends.concat(this.allExtendsStack[this.allExtendsStack.length - 1]);
          newAllExtends = newAllExtends.concat(this.doExtendChaining(newAllExtends, mediaNode.allExtends));
          this.allExtendsStack.push(newAllExtends);
        }
      }, {
        key: "visitMediaOut",
        value: function visitMediaOut(mediaNode) {
          var lastIndex = this.allExtendsStack.length - 1;
          this.allExtendsStack.length = lastIndex;
        }
      }, {
        key: "visitAtRule",
        value: function visitAtRule(atRuleNode, visitArgs) {
          var newAllExtends = atRuleNode.allExtends.concat(this.allExtendsStack[this.allExtendsStack.length - 1]);
          newAllExtends = newAllExtends.concat(this.doExtendChaining(newAllExtends, atRuleNode.allExtends));
          this.allExtendsStack.push(newAllExtends);
        }
      }, {
        key: "visitAtRuleOut",
        value: function visitAtRuleOut(atRuleNode) {
          var lastIndex = this.allExtendsStack.length - 1;
          this.allExtendsStack.length = lastIndex;
        }
      }]);
  
      return ProcessExtendsVisitor;
    }();
  
    var JoinSelectorVisitor =
    /*#__PURE__*/
    function () {
      function JoinSelectorVisitor() {
        _classCallCheck(this, JoinSelectorVisitor);
  
        this.contexts = [[]];
        this._visitor = new Visitor(this);
      }
  
      _createClass(JoinSelectorVisitor, [{
        key: "run",
        value: function run(root) {
          return this._visitor.visit(root);
        }
      }, {
        key: "visitDeclaration",
        value: function visitDeclaration(declNode, visitArgs) {
          visitArgs.visitDeeper = false;
        }
      }, {
        key: "visitMixinDefinition",
        value: function visitMixinDefinition(mixinDefinitionNode, visitArgs) {
          visitArgs.visitDeeper = false;
        }
      }, {
        key: "visitRuleset",
        value: function visitRuleset(rulesetNode, visitArgs) {
          var context = this.contexts[this.contexts.length - 1];
          var paths = [];
          var selectors;
          this.contexts.push(paths);
  
          if (!rulesetNode.root) {
            selectors = rulesetNode.selectors;
  
            if (selectors) {
              selectors = selectors.filter(function (selector) {
                return selector.getIsOutput();
              });
              rulesetNode.selectors = selectors.length ? selectors : selectors = null;
  
              if (selectors) {
                rulesetNode.joinSelectors(paths, context, selectors);
              }
            }
  
            if (!selectors) {
              rulesetNode.rules = null;
            }
  
            rulesetNode.paths = paths;
          }
        }
      }, {
        key: "visitRulesetOut",
        value: function visitRulesetOut(rulesetNode) {
          this.contexts.length = this.contexts.length - 1;
        }
      }, {
        key: "visitMedia",
        value: function visitMedia(mediaNode, visitArgs) {
          var context = this.contexts[this.contexts.length - 1];
          mediaNode.rules[0].root = context.length === 0 || context[0].multiMedia;
        }
      }, {
        key: "visitAtRule",
        value: function visitAtRule(atRuleNode, visitArgs) {
          var context = this.contexts[this.contexts.length - 1];
  
          if (atRuleNode.rules && atRuleNode.rules.length) {
            atRuleNode.rules[0].root = atRuleNode.isRooted || context.length === 0 || null;
          }
        }
      }]);
  
      return JoinSelectorVisitor;
    }();
  
    var CSSVisitorUtils =
    /*#__PURE__*/
    function () {
      function CSSVisitorUtils(context) {
        _classCallCheck(this, CSSVisitorUtils);
  
        this._visitor = new Visitor(this);
        this._context = context;
      }
  
      _createClass(CSSVisitorUtils, [{
        key: "containsSilentNonBlockedChild",
        value: function containsSilentNonBlockedChild(bodyRules) {
          var rule;
  
          if (!bodyRules) {
            return false;
          }
  
          for (var r = 0; r < bodyRules.length; r++) {
            rule = bodyRules[r];
  
            if (rule.isSilent && rule.isSilent(this._context) && !rule.blocksVisibility()) {
              // the atrule contains something that was referenced (likely by extend)
              // therefore it needs to be shown in output too
              return true;
            }
          }
  
          return false;
        }
      }, {
        key: "keepOnlyVisibleChilds",
        value: function keepOnlyVisibleChilds(owner) {
          if (owner && owner.rules) {
            owner.rules = owner.rules.filter(function (thing) {
              return thing.isVisible();
            });
          }
        }
      }, {
        key: "isEmpty",
        value: function isEmpty(owner) {
          return owner && owner.rules ? owner.rules.length === 0 : true;
        }
      }, {
        key: "hasVisibleSelector",
        value: function hasVisibleSelector(rulesetNode) {
          return rulesetNode && rulesetNode.paths ? rulesetNode.paths.length > 0 : false;
        }
      }, {
        key: "resolveVisibility",
        value: function resolveVisibility(node, originalRules) {
          if (!node.blocksVisibility()) {
            if (this.isEmpty(node) && !this.containsSilentNonBlockedChild(originalRules)) {
              return;
            }
  
            return node;
          }
  
          var compiledRulesBody = node.rules[0];
          this.keepOnlyVisibleChilds(compiledRulesBody);
  
          if (this.isEmpty(compiledRulesBody)) {
            return;
          }
  
          node.ensureVisibility();
          node.removeVisibilityBlock();
          return node;
        }
      }, {
        key: "isVisibleRuleset",
        value: function isVisibleRuleset(rulesetNode) {
          if (rulesetNode.firstRoot) {
            return true;
          }
  
          if (this.isEmpty(rulesetNode)) {
            return false;
          }
  
          if (!rulesetNode.root && !this.hasVisibleSelector(rulesetNode)) {
            return false;
          }
  
          return true;
        }
      }]);
  
      return CSSVisitorUtils;
    }();
  
    var ToCSSVisitor = function ToCSSVisitor(context) {
      this._visitor = new Visitor(this);
      this._context = context;
      this.utils = new CSSVisitorUtils(context);
    };
  
    ToCSSVisitor.prototype = {
      isReplacing: true,
      run: function run(root) {
        return this._visitor.visit(root);
      },
      visitDeclaration: function visitDeclaration(declNode, visitArgs) {
        if (declNode.blocksVisibility() || declNode.variable) {
          return;
        }
  
        return declNode;
      },
      visitMixinDefinition: function visitMixinDefinition(mixinNode, visitArgs) {
        // mixin definitions do not get eval'd - this means they keep state
        // so we have to clear that state here so it isn't used if toCSS is called twice
        mixinNode.frames = [];
      },
      visitExtend: function visitExtend(extendNode, visitArgs) {},
      visitComment: function visitComment(commentNode, visitArgs) {
        if (commentNode.blocksVisibility() || commentNode.isSilent(this._context)) {
          return;
        }
  
        return commentNode;
      },
      visitMedia: function visitMedia(mediaNode, visitArgs) {
        var originalRules = mediaNode.rules[0].rules;
        mediaNode.accept(this._visitor);
        visitArgs.visitDeeper = false;
        return this.utils.resolveVisibility(mediaNode, originalRules);
      },
      visitImport: function visitImport(importNode, visitArgs) {
        if (importNode.blocksVisibility()) {
          return;
        }
  
        return importNode;
      },
      visitAtRule: function visitAtRule(atRuleNode, visitArgs) {
        if (atRuleNode.rules && atRuleNode.rules.length) {
          return this.visitAtRuleWithBody(atRuleNode, visitArgs);
        } else {
          return this.visitAtRuleWithoutBody(atRuleNode, visitArgs);
        }
      },
      visitAnonymous: function visitAnonymous(anonymousNode, visitArgs) {
        if (!anonymousNode.blocksVisibility()) {
          anonymousNode.accept(this._visitor);
          return anonymousNode;
        }
      },
      visitAtRuleWithBody: function visitAtRuleWithBody(atRuleNode, visitArgs) {
        // if there is only one nested ruleset and that one has no path, then it is
        // just fake ruleset
        function hasFakeRuleset(atRuleNode) {
          var bodyRules = atRuleNode.rules;
          return bodyRules.length === 1 && (!bodyRules[0].paths || bodyRules[0].paths.length === 0);
        }
  
        function getBodyRules(atRuleNode) {
          var nodeRules = atRuleNode.rules;
  
          if (hasFakeRuleset(atRuleNode)) {
            return nodeRules[0].rules;
          }
  
          return nodeRules;
        } // it is still true that it is only one ruleset in array
        // this is last such moment
        // process childs
  
  
        var originalRules = getBodyRules(atRuleNode);
        atRuleNode.accept(this._visitor);
        visitArgs.visitDeeper = false;
  
        if (!this.utils.isEmpty(atRuleNode)) {
          this._mergeRules(atRuleNode.rules[0].rules);
        }
  
        return this.utils.resolveVisibility(atRuleNode, originalRules);
      },
      visitAtRuleWithoutBody: function visitAtRuleWithoutBody(atRuleNode, visitArgs) {
        if (atRuleNode.blocksVisibility()) {
          return;
        }
  
        if (atRuleNode.name === '@charset') {
          // Only output the debug info together with subsequent @charset definitions
          // a comment (or @media statement) before the actual @charset atrule would
          // be considered illegal css as it has to be on the first line
          if (this.charset) {
            if (atRuleNode.debugInfo) {
              var comment = new tree.Comment("/* ".concat(atRuleNode.toCSS(this._context).replace(/\n/g, ''), " */\n"));
              comment.debugInfo = atRuleNode.debugInfo;
              return this._visitor.visit(comment);
            }
  
            return;
          }
  
          this.charset = true;
        }
  
        return atRuleNode;
      },
      checkValidNodes: function checkValidNodes(rules, isRoot) {
        if (!rules) {
          return;
        }
  
        for (var i = 0; i < rules.length; i++) {
          var ruleNode = rules[i];
  
          if (isRoot && ruleNode instanceof tree.Declaration && !ruleNode.variable) {
            throw {
              message: 'Properties must be inside selector blocks. They cannot be in the root',
              index: ruleNode.getIndex(),
              filename: ruleNode.fileInfo() && ruleNode.fileInfo().filename
            };
          }
  
          if (ruleNode instanceof tree.Call) {
            throw {
              message: "Function '".concat(ruleNode.name, "' is undefined"),
              index: ruleNode.getIndex(),
              filename: ruleNode.fileInfo() && ruleNode.fileInfo().filename
            };
          }
  
          if (ruleNode.type && !ruleNode.allowRoot) {
            throw {
              message: "".concat(ruleNode.type, " node returned by a function is not valid here"),
              index: ruleNode.getIndex(),
              filename: ruleNode.fileInfo() && ruleNode.fileInfo().filename
            };
          }
        }
      },
      visitRuleset: function visitRuleset(rulesetNode, visitArgs) {
        // at this point rulesets are nested into each other
        var rule;
        var rulesets = [];
        this.checkValidNodes(rulesetNode.rules, rulesetNode.firstRoot);
  
        if (!rulesetNode.root) {
          // remove invisible paths
          this._compileRulesetPaths(rulesetNode); // remove rulesets from this ruleset body and compile them separately
  
  
          var nodeRules = rulesetNode.rules;
          var nodeRuleCnt = nodeRules ? nodeRules.length : 0;
  
          for (var i = 0; i < nodeRuleCnt;) {
            rule = nodeRules[i];
  
            if (rule && rule.rules) {
              // visit because we are moving them out from being a child
              rulesets.push(this._visitor.visit(rule));
              nodeRules.splice(i, 1);
              nodeRuleCnt--;
              continue;
            }
  
            i++;
          } // accept the visitor to remove rules and refactor itself
          // then we can decide nogw whether we want it or not
          // compile body
  
  
          if (nodeRuleCnt > 0) {
            rulesetNode.accept(this._visitor);
          } else {
            rulesetNode.rules = null;
          }
  
          visitArgs.visitDeeper = false;
        } else {
          // if (! rulesetNode.root) {
          rulesetNode.accept(this._visitor);
          visitArgs.visitDeeper = false;
        }
  
        if (rulesetNode.rules) {
          this._mergeRules(rulesetNode.rules);
  
          this._removeDuplicateRules(rulesetNode.rules);
        } // now decide whether we keep the ruleset
  
  
        if (this.utils.isVisibleRuleset(rulesetNode)) {
          rulesetNode.ensureVisibility();
          rulesets.splice(0, 0, rulesetNode);
        }
  
        if (rulesets.length === 1) {
          return rulesets[0];
        }
  
        return rulesets;
      },
      _compileRulesetPaths: function _compileRulesetPaths(rulesetNode) {
        if (rulesetNode.paths) {
          rulesetNode.paths = rulesetNode.paths.filter(function (p) {
            var i;
  
            if (p[0].elements[0].combinator.value === ' ') {
              p[0].elements[0].combinator = new tree.Combinator('');
            }
  
            for (i = 0; i < p.length; i++) {
              if (p[i].isVisible() && p[i].getIsOutput()) {
                return true;
              }
            }
  
            return false;
          });
        }
      },
      _removeDuplicateRules: function _removeDuplicateRules(rules) {
        if (!rules) {
          return;
        } // remove duplicates
  
  
        var ruleCache = {};
        var ruleList;
        var rule;
        var i;
  
        for (i = rules.length - 1; i >= 0; i--) {
          rule = rules[i];
  
          if (rule instanceof tree.Declaration) {
            if (!ruleCache[rule.name]) {
              ruleCache[rule.name] = rule;
            } else {
              ruleList = ruleCache[rule.name];
  
              if (ruleList instanceof tree.Declaration) {
                ruleList = ruleCache[rule.name] = [ruleCache[rule.name].toCSS(this._context)];
              }
  
              var ruleCSS = rule.toCSS(this._context);
  
              if (ruleList.indexOf(ruleCSS) !== -1) {
                rules.splice(i, 1);
              } else {
                ruleList.push(ruleCSS);
              }
            }
          }
        }
      },
      _mergeRules: function _mergeRules(rules) {
        if (!rules) {
          return;
        }
  
        var groups = {};
        var groupsArr = [];
  
        for (var i = 0; i < rules.length; i++) {
          var rule = rules[i];
  
          if (rule.merge) {
            var key = rule.name;
            groups[key] ? rules.splice(i--, 1) : groupsArr.push(groups[key] = []);
            groups[key].push(rule);
          }
        }
  
        groupsArr.forEach(function (group) {
          if (group.length > 0) {
            var result = group[0];
            var space = [];
            var comma = [new tree.Expression(space)];
            group.forEach(function (rule) {
              if (rule.merge === '+' && space.length > 0) {
                comma.push(new tree.Expression(space = []));
              }
  
              space.push(rule.value);
              result.important = result.important || rule.important;
            });
            result.value = new tree.Value(comma);
          }
        });
      }
    };
  
    var visitors = {
      Visitor: Visitor,
      ImportVisitor: ImportVisitor,
      MarkVisibleSelectorsVisitor: SetTreeVisibilityVisitor,
      ExtendVisitor: ProcessExtendsVisitor,
      JoinSelectorVisitor: JoinSelectorVisitor,
      ToCSSVisitor: ToCSSVisitor
    };
  
    // Split the input into chunks.
    var chunker = (function (input, fail) {
      var len = input.length;
      var level = 0;
      var parenLevel = 0;
      var lastOpening;
      var lastOpeningParen;
      var lastMultiComment;
      var lastMultiCommentEndBrace;
      var chunks = [];
      var emitFrom = 0;
      var chunkerCurrentIndex;
      var currentChunkStartIndex;
      var cc;
      var cc2;
      var matched;
  
      function emitChunk(force) {
        var len = chunkerCurrentIndex - emitFrom;
  
        if (len < 512 && !force || !len) {
          return;
        }
  
        chunks.push(input.slice(emitFrom, chunkerCurrentIndex + 1));
        emitFrom = chunkerCurrentIndex + 1;
      }
  
      for (chunkerCurrentIndex = 0; chunkerCurrentIndex < len; chunkerCurrentIndex++) {
        cc = input.charCodeAt(chunkerCurrentIndex);
  
        if (cc >= 97 && cc <= 122 || cc < 34) {
          // a-z or whitespace
          continue;
        }
  
        switch (cc) {
          case 40:
            // (
            parenLevel++;
            lastOpeningParen = chunkerCurrentIndex;
            continue;
  
          case 41:
            // )
            if (--parenLevel < 0) {
              return fail('missing opening `(`', chunkerCurrentIndex);
            }
  
            continue;
  
          case 59:
            // ;
            if (!parenLevel) {
              emitChunk();
            }
  
            continue;
  
          case 123:
            // {
            level++;
            lastOpening = chunkerCurrentIndex;
            continue;
  
          case 125:
            // }
            if (--level < 0) {
              return fail('missing opening `{`', chunkerCurrentIndex);
            }
  
            if (!level && !parenLevel) {
              emitChunk();
            }
  
            continue;
  
          case 92:
            // \
            if (chunkerCurrentIndex < len - 1) {
              chunkerCurrentIndex++;
              continue;
            }
  
            return fail('unescaped `\\`', chunkerCurrentIndex);
  
          case 34:
          case 39:
          case 96:
            // ", ' and `
            matched = 0;
            currentChunkStartIndex = chunkerCurrentIndex;
  
            for (chunkerCurrentIndex = chunkerCurrentIndex + 1; chunkerCurrentIndex < len; chunkerCurrentIndex++) {
              cc2 = input.charCodeAt(chunkerCurrentIndex);
  
              if (cc2 > 96) {
                continue;
              }
  
              if (cc2 == cc) {
                matched = 1;
                break;
              }
  
              if (cc2 == 92) {
                // \
                if (chunkerCurrentIndex == len - 1) {
                  return fail('unescaped `\\`', chunkerCurrentIndex);
                }
  
                chunkerCurrentIndex++;
              }
            }
  
            if (matched) {
              continue;
            }
  
            return fail("unmatched `".concat(String.fromCharCode(cc), "`"), currentChunkStartIndex);
  
          case 47:
            // /, check for comment
            if (parenLevel || chunkerCurrentIndex == len - 1) {
              continue;
            }
  
            cc2 = input.charCodeAt(chunkerCurrentIndex + 1);
  
            if (cc2 == 47) {
              // //, find lnfeed
              for (chunkerCurrentIndex = chunkerCurrentIndex + 2; chunkerCurrentIndex < len; chunkerCurrentIndex++) {
                cc2 = input.charCodeAt(chunkerCurrentIndex);
  
                if (cc2 <= 13 && (cc2 == 10 || cc2 == 13)) {
                  break;
                }
              }
            } else if (cc2 == 42) {
              // /*, find */
              lastMultiComment = currentChunkStartIndex = chunkerCurrentIndex;
  
              for (chunkerCurrentIndex = chunkerCurrentIndex + 2; chunkerCurrentIndex < len - 1; chunkerCurrentIndex++) {
                cc2 = input.charCodeAt(chunkerCurrentIndex);
  
                if (cc2 == 125) {
                  lastMultiCommentEndBrace = chunkerCurrentIndex;
                }
  
                if (cc2 != 42) {
                  continue;
                }
  
                if (input.charCodeAt(chunkerCurrentIndex + 1) == 47) {
                  break;
                }
              }
  
              if (chunkerCurrentIndex == len - 1) {
                return fail('missing closing `*/`', currentChunkStartIndex);
              }
  
              chunkerCurrentIndex++;
            }
  
            continue;
  
          case 42:
            // *, check for unmatched */
            if (chunkerCurrentIndex < len - 1 && input.charCodeAt(chunkerCurrentIndex + 1) == 47) {
              return fail('unmatched `/*`', chunkerCurrentIndex);
            }
  
            continue;
        }
      }
  
      if (level !== 0) {
        if (lastMultiComment > lastOpening && lastMultiCommentEndBrace > lastMultiComment) {
          return fail('missing closing `}` or `*/`', lastOpening);
        } else {
          return fail('missing closing `}`', lastOpening);
        }
      } else if (parenLevel !== 0) {
        return fail('missing closing `)`', lastOpeningParen);
      }
  
      emitChunk(true);
      return chunks;
    });
  
    var getParserInput = (function () {
      var // Less input string
      input;
      var // current chunk
      j;
      var // holds state for backtracking
      saveStack = [];
      var // furthest index the parser has gone to
      furthest;
      var // if this is furthest we got to, this is the probably cause
      furthestPossibleErrorMessage;
      var // chunkified input
      chunks;
      var // current chunk
      current;
      var // index of current chunk, in `input`
      currentPos;
      var parserInput = {};
      var CHARCODE_SPACE = 32;
      var CHARCODE_TAB = 9;
      var CHARCODE_LF = 10;
      var CHARCODE_CR = 13;
      var CHARCODE_PLUS = 43;
      var CHARCODE_COMMA = 44;
      var CHARCODE_FORWARD_SLASH = 47;
      var CHARCODE_9 = 57;
  
      function skipWhitespace(length) {
        var oldi = parserInput.i;
        var oldj = j;
        var curr = parserInput.i - currentPos;
        var endIndex = parserInput.i + current.length - curr;
        var mem = parserInput.i += length;
        var inp = input;
        var c;
        var nextChar;
        var comment;
  
        for (; parserInput.i < endIndex; parserInput.i++) {
          c = inp.charCodeAt(parserInput.i);
  
          if (parserInput.autoCommentAbsorb && c === CHARCODE_FORWARD_SLASH) {
            nextChar = inp.charAt(parserInput.i + 1);
  
            if (nextChar === '/') {
              comment = {
                index: parserInput.i,
                isLineComment: true
              };
              var nextNewLine = inp.indexOf('\n', parserInput.i + 2);
  
              if (nextNewLine < 0) {
                nextNewLine = endIndex;
              }
  
              parserInput.i = nextNewLine;
              comment.text = inp.substr(comment.index, parserInput.i - comment.index);
              parserInput.commentStore.push(comment);
              continue;
            } else if (nextChar === '*') {
              var nextStarSlash = inp.indexOf('*/', parserInput.i + 2);
  
              if (nextStarSlash >= 0) {
                comment = {
                  index: parserInput.i,
                  text: inp.substr(parserInput.i, nextStarSlash + 2 - parserInput.i),
                  isLineComment: false
                };
                parserInput.i += comment.text.length - 1;
                parserInput.commentStore.push(comment);
                continue;
              }
            }
  
            break;
          }
  
          if (c !== CHARCODE_SPACE && c !== CHARCODE_LF && c !== CHARCODE_TAB && c !== CHARCODE_CR) {
            break;
          }
        }
  
        current = current.slice(length + parserInput.i - mem + curr);
        currentPos = parserInput.i;
  
        if (!current.length) {
          if (j < chunks.length - 1) {
            current = chunks[++j];
            skipWhitespace(0); // skip space at the beginning of a chunk
  
            return true; // things changed
          }
  
          parserInput.finished = true;
        }
  
        return oldi !== parserInput.i || oldj !== j;
      }
  
      parserInput.save = function () {
        currentPos = parserInput.i;
        saveStack.push({
          current: current,
          i: parserInput.i,
          j: j
        });
      };
  
      parserInput.restore = function (possibleErrorMessage) {
        if (parserInput.i > furthest || parserInput.i === furthest && possibleErrorMessage && !furthestPossibleErrorMessage) {
          furthest = parserInput.i;
          furthestPossibleErrorMessage = possibleErrorMessage;
        }
  
        var state = saveStack.pop();
        current = state.current;
        currentPos = parserInput.i = state.i;
        j = state.j;
      };
  
      parserInput.forget = function () {
        saveStack.pop();
      };
  
      parserInput.isWhitespace = function (offset) {
        var pos = parserInput.i + (offset || 0);
        var code = input.charCodeAt(pos);
        return code === CHARCODE_SPACE || code === CHARCODE_CR || code === CHARCODE_TAB || code === CHARCODE_LF;
      }; // Specialization of $(tok)
  
  
      parserInput.$re = function (tok) {
        if (parserInput.i > currentPos) {
          current = current.slice(parserInput.i - currentPos);
          currentPos = parserInput.i;
        }
  
        var m = tok.exec(current);
  
        if (!m) {
          return null;
        }
  
        skipWhitespace(m[0].length);
  
        if (typeof m === 'string') {
          return m;
        }
  
        return m.length === 1 ? m[0] : m;
      };
  
      parserInput.$char = function (tok) {
        if (input.charAt(parserInput.i) !== tok) {
          return null;
        }
  
        skipWhitespace(1);
        return tok;
      };
  
      parserInput.$str = function (tok) {
        var tokLength = tok.length; // https://jsperf.com/string-startswith/21
  
        for (var i = 0; i < tokLength; i++) {
          if (input.charAt(parserInput.i + i) !== tok.charAt(i)) {
            return null;
          }
        }
  
        skipWhitespace(tokLength);
        return tok;
      };
  
      parserInput.$quoted = function (loc) {
        var pos = loc || parserInput.i;
        var startChar = input.charAt(pos);
  
        if (startChar !== '\'' && startChar !== '"') {
          return;
        }
  
        var length = input.length;
        var currentPosition = pos;
  
        for (var i = 1; i + currentPosition < length; i++) {
          var nextChar = input.charAt(i + currentPosition);
  
          switch (nextChar) {
            case '\\':
              i++;
              continue;
  
            case '\r':
            case '\n':
              break;
  
            case startChar:
              var str = input.substr(currentPosition, i + 1);
  
              if (!loc && loc !== 0) {
                skipWhitespace(i + 1);
                return str;
              }
  
              return [startChar, str];
  
            default:
          }
        }
  
        return null;
      };
      /**
       * Permissive parsing. Ignores everything except matching {} [] () and quotes
       * until matching token (outside of blocks)
       */
  
  
      parserInput.$parseUntil = function (tok) {
        var quote = '';
        var returnVal = null;
        var inComment = false;
        var blockDepth = 0;
        var blockStack = [];
        var parseGroups = [];
        var length = input.length;
        var startPos = parserInput.i;
        var lastPos = parserInput.i;
        var i = parserInput.i;
        var loop = true;
        var testChar;
  
        if (typeof tok === 'string') {
          testChar = function testChar(char) {
            return char === tok;
          };
        } else {
          testChar = function testChar(char) {
            return tok.test(char);
          };
        }
  
        do {
          var nextChar = input.charAt(i);
  
          if (blockDepth === 0 && testChar(nextChar)) {
            returnVal = input.substr(lastPos, i - lastPos);
  
            if (returnVal) {
              parseGroups.push(returnVal);
            } else {
              parseGroups.push(' ');
            }
  
            returnVal = parseGroups;
            skipWhitespace(i - startPos);
            loop = false;
          } else {
            if (inComment) {
              if (nextChar === '*' && input.charAt(i + 1) === '/') {
                i++;
                blockDepth--;
                inComment = false;
              }
  
              i++;
              continue;
            }
  
            switch (nextChar) {
              case '\\':
                i++;
                nextChar = input.charAt(i);
                parseGroups.push(input.substr(lastPos, i - lastPos + 1));
                lastPos = i + 1;
                break;
  
              case '/':
                if (input.charAt(i + 1) === '*') {
                  i++;
                  inComment = true;
                  blockDepth++;
                }
  
                break;
  
              case '\'':
              case '"':
                quote = parserInput.$quoted(i);
  
                if (quote) {
                  parseGroups.push(input.substr(lastPos, i - lastPos), quote);
                  i += quote[1].length - 1;
                  lastPos = i + 1;
                } else {
                  skipWhitespace(i - startPos);
                  returnVal = nextChar;
                  loop = false;
                }
  
                break;
  
              case '{':
                blockStack.push('}');
                blockDepth++;
                break;
  
              case '(':
                blockStack.push(')');
                blockDepth++;
                break;
  
              case '[':
                blockStack.push(']');
                blockDepth++;
                break;
  
              case '}':
              case ')':
              case ']':
                var expected = blockStack.pop();
  
                if (nextChar === expected) {
                  blockDepth--;
                } else {
                  // move the parser to the error and return expected
                  skipWhitespace(i - startPos);
                  returnVal = expected;
                  loop = false;
                }
  
            }
  
            i++;
  
            if (i > length) {
              loop = false;
            }
          }
        } while (loop);
  
        return returnVal ? returnVal : null;
      };
  
      parserInput.autoCommentAbsorb = true;
      parserInput.commentStore = [];
      parserInput.finished = false; // Same as $(), but don't change the state of the parser,
      // just return the match.
  
      parserInput.peek = function (tok) {
        if (typeof tok === 'string') {
          // https://jsperf.com/string-startswith/21
          for (var i = 0; i < tok.length; i++) {
            if (input.charAt(parserInput.i + i) !== tok.charAt(i)) {
              return false;
            }
          }
  
          return true;
        } else {
          return tok.test(current);
        }
      }; // Specialization of peek()
      // TODO remove or change some currentChar calls to peekChar
  
  
      parserInput.peekChar = function (tok) {
        return input.charAt(parserInput.i) === tok;
      };
  
      parserInput.currentChar = function () {
        return input.charAt(parserInput.i);
      };
  
      parserInput.prevChar = function () {
        return input.charAt(parserInput.i - 1);
      };
  
      parserInput.getInput = function () {
        return input;
      };
  
      parserInput.peekNotNumeric = function () {
        var c = input.charCodeAt(parserInput.i); // Is the first char of the dimension 0-9, '.', '+' or '-'
  
        return c > CHARCODE_9 || c < CHARCODE_PLUS || c === CHARCODE_FORWARD_SLASH || c === CHARCODE_COMMA;
      };
  
      parserInput.start = function (str, chunkInput, failFunction) {
        input = str;
        parserInput.i = j = currentPos = furthest = 0; // chunking apparently makes things quicker (but my tests indicate
        // it might actually make things slower in node at least)
        // and it is a non-perfect parse - it can't recognise
        // unquoted urls, meaning it can't distinguish comments
        // meaning comments with quotes or {}() in them get 'counted'
        // and then lead to parse errors.
        // In addition if the chunking chunks in the wrong place we might
        // not be able to parse a parser statement in one go
        // this is officially deprecated but can be switched on via an option
        // in the case it causes too much performance issues.
  
        if (chunkInput) {
          chunks = chunker(str, failFunction);
        } else {
          chunks = [str];
        }
  
        current = chunks[0];
        skipWhitespace(0);
      };
  
      parserInput.end = function () {
        var message;
        var isFinished = parserInput.i >= input.length;
  
        if (parserInput.i < furthest) {
          message = furthestPossibleErrorMessage;
          parserInput.i = furthest;
        }
  
        return {
          isFinished: isFinished,
          furthest: parserInput.i,
          furthestPossibleErrorMessage: message,
          furthestReachedEnd: parserInput.i >= input.length - 1,
          furthestChar: input[parserInput.i]
        };
      };
  
      return parserInput;
    });
  
    // less.js - parser
    //
    //    A relatively straight-forward predictive parser.
    //    There is no tokenization/lexing stage, the input is parsed
    //    in one sweep.
    //
    //    To make the parser fast enough to run in the browser, several
    //    optimization had to be made:
    //
    //    - Matching and slicing on a huge input is often cause of slowdowns.
    //      The solution is to chunkify the input into smaller strings.
    //      The chunks are stored in the `chunks` var,
    //      `j` holds the current chunk index, and `currentPos` holds
    //      the index of the current chunk in relation to `input`.
    //      This gives us an almost 4x speed-up.
    //
    //    - In many cases, we don't need to match individual tokens;
    //      for example, if a value doesn't hold any variables, operations
    //      or dynamic references, the parser can effectively 'skip' it,
    //      treating it as a literal.
    //      An example would be '1px solid #000' - which evaluates to itself,
    //      we don't need to know what the individual components are.
    //      The drawback, of course is that you don't get the benefits of
    //      syntax-checking on the CSS. This gives us a 50% speed-up in the parser,
    //      and a smaller speed-up in the code-gen.
    //
    //
    //    Token matching is done with the `$` function, which either takes
    //    a terminal string or regexp, or a non-terminal function to call.
    //    It also takes care of moving all the indices forwards.
    //
  
    var Parser = function Parser(context, imports, fileInfo) {
      var parsers;
      var parserInput = getParserInput();
  
      function error(msg, type) {
        throw new LessError({
          index: parserInput.i,
          filename: fileInfo.filename,
          type: type || 'Syntax',
          message: msg
        }, imports);
      }
  
      function expect(arg, msg) {
        // some older browsers return typeof 'function' for RegExp
        var result = arg instanceof Function ? arg.call(parsers) : parserInput.$re(arg);
  
        if (result) {
          return result;
        }
  
        error(msg || (typeof arg === 'string' ? "expected '".concat(arg, "' got '").concat(parserInput.currentChar(), "'") : 'unexpected token'));
      } // Specialization of expect()
  
  
      function expectChar(arg, msg) {
        if (parserInput.$char(arg)) {
          return arg;
        }
  
        error(msg || "expected '".concat(arg, "' got '").concat(parserInput.currentChar(), "'"));
      }
  
      function getDebugInfo(index) {
        var filename = fileInfo.filename;
        return {
          lineNumber: getLocation(index, parserInput.getInput()).line + 1,
          fileName: filename
        };
      }
      /**
       *  Used after initial parsing to create nodes on the fly
       * 
       *  @param {String} str          - string to parse 
       *  @param {Array}  parseList    - array of parsers to run input through e.g. ["value", "important"]
       *  @param {Number} currentIndex - start number to begin indexing
       *  @param {Object} fileInfo     - fileInfo to attach to created nodes
       */
  
  
      function parseNode(str, parseList, currentIndex, fileInfo, callback) {
        var result;
        var returnNodes = [];
        var parser = parserInput;
  
        try {
          parser.start(str, false, function fail(msg, index) {
            callback({
              message: msg,
              index: index + currentIndex
            });
          });
  
          for (var x = 0, p, i; p = parseList[x]; x++) {
            i = parser.i;
            result = parsers[p]();
  
            if (result) {
              try {
                result._index = i + currentIndex;
                result._fileInfo = fileInfo;
              } catch (e) {}
  
              returnNodes.push(result);
            } else {
              returnNodes.push(null);
            }
          }
  
          var endInfo = parser.end();
  
          if (endInfo.isFinished) {
            callback(null, returnNodes);
          } else {
            callback(true, null);
          }
        } catch (e) {
          throw new LessError({
            index: e.index + currentIndex,
            message: e.message
          }, imports, fileInfo.filename);
        }
      } //
      // The Parser
      //
  
  
      return {
        parserInput: parserInput,
        imports: imports,
        fileInfo: fileInfo,
        parseNode: parseNode,
        //
        // Parse an input string into an abstract syntax tree,
        // @param str A string containing 'less' markup
        // @param callback call `callback` when done.
        // @param [additionalData] An optional map which can contains vars - a map (key, value) of variables to apply
        //
        parse: function parse(str, callback, additionalData) {
          var root;
          var error = null;
          var globalVars;
          var modifyVars;
          var ignored;
          var preText = '';
          globalVars = additionalData && additionalData.globalVars ? "".concat(Parser.serializeVars(additionalData.globalVars), "\n") : '';
          modifyVars = additionalData && additionalData.modifyVars ? "\n".concat(Parser.serializeVars(additionalData.modifyVars)) : '';
  
          if (context.pluginManager) {
            var preProcessors = context.pluginManager.getPreProcessors();
  
            for (var i = 0; i < preProcessors.length; i++) {
              str = preProcessors[i].process(str, {
                context: context,
                imports: imports,
                fileInfo: fileInfo
              });
            }
          }
  
          if (globalVars || additionalData && additionalData.banner) {
            preText = (additionalData && additionalData.banner ? additionalData.banner : '') + globalVars;
            ignored = imports.contentsIgnoredChars;
            ignored[fileInfo.filename] = ignored[fileInfo.filename] || 0;
            ignored[fileInfo.filename] += preText.length;
          }
  
          str = str.replace(/\r\n?/g, '\n'); // Remove potential UTF Byte Order Mark
  
          str = preText + str.replace(/^\uFEFF/, '') + modifyVars;
          imports.contents[fileInfo.filename] = str; // Start with the primary rule.
          // The whole syntax tree is held under a Ruleset node,
          // with the `root` property set to true, so no `{}` are
          // output. The callback is called when the input is parsed.
  
          try {
            parserInput.start(str, context.chunkInput, function fail(msg, index) {
              throw new LessError({
                index: index,
                type: 'Parse',
                message: msg,
                filename: fileInfo.filename
              }, imports);
            });
            tree.Node.prototype.parse = this;
            root = new tree.Ruleset(null, this.parsers.primary());
            tree.Node.prototype.rootNode = root;
            root.root = true;
            root.firstRoot = true;
            root.functionRegistry = functionRegistry.inherit();
          } catch (e) {
            return callback(new LessError(e, imports, fileInfo.filename));
          } // If `i` is smaller than the `input.length - 1`,
          // it means the parser wasn't able to parse the whole
          // string, so we've got a parsing error.
          //
          // We try to extract a \n delimited string,
          // showing the line where the parse error occurred.
          // We split it up into two parts (the part which parsed,
          // and the part which didn't), so we can color them differently.
  
  
          var endInfo = parserInput.end();
  
          if (!endInfo.isFinished) {
            var message = endInfo.furthestPossibleErrorMessage;
  
            if (!message) {
              message = 'Unrecognised input';
  
              if (endInfo.furthestChar === '}') {
                message += '. Possibly missing opening \'{\'';
              } else if (endInfo.furthestChar === ')') {
                message += '. Possibly missing opening \'(\'';
              } else if (endInfo.furthestReachedEnd) {
                message += '. Possibly missing something';
              }
            }
  
            error = new LessError({
              type: 'Parse',
              message: message,
              index: endInfo.furthest,
              filename: fileInfo.filename
            }, imports);
          }
  
          var finish = function finish(e) {
            e = error || e || imports.error;
  
            if (e) {
              if (!(e instanceof LessError)) {
                e = new LessError(e, imports, fileInfo.filename);
              }
  
              return callback(e);
            } else {
              return callback(null, root);
            }
          };
  
          if (context.processImports !== false) {
            new visitors.ImportVisitor(imports, finish).run(root);
          } else {
            return finish();
          }
        },
        //
        // Here in, the parsing rules/functions
        //
        // The basic structure of the syntax tree generated is as follows:
        //
        //   Ruleset ->  Declaration -> Value -> Expression -> Entity
        //
        // Here's some Less code:
        //
        //    .class {
        //      color: #fff;
        //      border: 1px solid #000;
        //      width: @w + 4px;
        //      > .child {...}
        //    }
        //
        // And here's what the parse tree might look like:
        //
        //     Ruleset (Selector '.class', [
        //         Declaration ("color",  Value ([Expression [Color #fff]]))
        //         Declaration ("border", Value ([Expression [Dimension 1px][Keyword "solid"][Color #000]]))
        //         Declaration ("width",  Value ([Expression [Operation " + " [Variable "@w"][Dimension 4px]]]))
        //         Ruleset (Selector [Element '>', '.child'], [...])
        //     ])
        //
        //  In general, most rules will try to parse a token with the `$re()` function, and if the return
        //  value is truly, will return a new node, of the relevant type. Sometimes, we need to check
        //  first, before parsing, that's when we use `peek()`.
        //
        parsers: parsers = {
          //
          // The `primary` rule is the *entry* and *exit* point of the parser.
          // The rules here can appear at any level of the parse tree.
          //
          // The recursive nature of the grammar is an interplay between the `block`
          // rule, which represents `{ ... }`, the `ruleset` rule, and this `primary` rule,
          // as represented by this simplified grammar:
          //
          //     primary  →  (ruleset | declaration)+
          //     ruleset  →  selector+ block
          //     block    →  '{' primary '}'
          //
          // Only at one point is the primary rule not called from the
          // block rule: at the root level.
          //
          primary: function primary() {
            var mixin = this.mixin;
            var root = [];
            var node;
  
            while (true) {
              while (true) {
                node = this.comment();
  
                if (!node) {
                  break;
                }
  
                root.push(node);
              } // always process comments before deciding if finished
  
  
              if (parserInput.finished) {
                break;
              }
  
              if (parserInput.peek('}')) {
                break;
              }
  
              node = this.extendRule();
  
              if (node) {
                root = root.concat(node);
                continue;
              }
  
              node = mixin.definition() || this.declaration() || this.ruleset() || mixin.call(false, false) || this.variableCall() || this.entities.call() || this.atrule();
  
              if (node) {
                root.push(node);
              } else {
                var foundSemiColon = false;
  
                while (parserInput.$char(';')) {
                  foundSemiColon = true;
                }
  
                if (!foundSemiColon) {
                  break;
                }
              }
            }
  
            return root;
          },
          // comments are collected by the main parsing mechanism and then assigned to nodes
          // where the current structure allows it
          comment: function comment() {
            if (parserInput.commentStore.length) {
              var comment = parserInput.commentStore.shift();
              return new tree.Comment(comment.text, comment.isLineComment, comment.index, fileInfo);
            }
          },
          //
          // Entities are tokens which can be found inside an Expression
          //
          entities: {
            mixinLookup: function mixinLookup() {
              return parsers.mixin.call(true, true);
            },
            //
            // A string, which supports escaping " and '
            //
            //     "milky way" 'he\'s the one!'
            //
            quoted: function quoted(forceEscaped) {
              var str;
              var index = parserInput.i;
              var isEscaped = false;
              parserInput.save();
  
              if (parserInput.$char('~')) {
                isEscaped = true;
              } else if (forceEscaped) {
                parserInput.restore();
                return;
              }
  
              str = parserInput.$quoted();
  
              if (!str) {
                parserInput.restore();
                return;
              }
  
              parserInput.forget();
              return new tree.Quoted(str.charAt(0), str.substr(1, str.length - 2), isEscaped, index, fileInfo);
            },
            //
            // A catch-all word, such as:
            //
            //     black border-collapse
            //
            keyword: function keyword() {
              var k = parserInput.$char('%') || parserInput.$re(/^\[?(?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+\]?/);
  
              if (k) {
                return tree.Color.fromKeyword(k) || new tree.Keyword(k);
              }
            },
            //
            // A function call
            //
            //     rgb(255, 0, 255)
            //
            // The arguments are parsed with the `entities.arguments` parser.
            //
            call: function call() {
              var name;
              var args;
              var func;
              var index = parserInput.i; // http://jsperf.com/case-insensitive-regex-vs-strtolower-then-regex/18
  
              if (parserInput.peek(/^url\(/i)) {
                return;
              }
  
              parserInput.save();
              name = parserInput.$re(/^([\w-]+|%|progid:[\w\.]+)\(/);
  
              if (!name) {
                parserInput.forget();
                return;
              }
  
              name = name[1];
              func = this.customFuncCall(name);
  
              if (func) {
                args = func.parse();
  
                if (args && func.stop) {
                  parserInput.forget();
                  return args;
                }
              }
  
              args = this.arguments(args);
  
              if (!parserInput.$char(')')) {
                parserInput.restore('Could not parse call arguments or missing \')\'');
                return;
              }
  
              parserInput.forget();
              return new tree.Call(name, args, index, fileInfo);
            },
            //
            // Parsing rules for functions with non-standard args, e.g.:
            //
            //     boolean(not(2 > 1))
            //
            //     This is a quick prototype, to be modified/improved when
            //     more custom-parsed funcs come (e.g. `selector(...)`)
            //
            customFuncCall: function customFuncCall(name) {
              /* Ideally the table is to be moved out of here for faster perf.,
                 but it's quite tricky since it relies on all these `parsers`
                 and `expect` available only here */
              return {
                alpha: f(parsers.ieAlpha, true),
                boolean: f(condition),
                'if': f(condition)
              }[name.toLowerCase()];
  
              function f(parse, stop) {
                return {
                  parse: parse,
                  // parsing function
                  stop: stop // when true - stop after parse() and return its result, 
                  // otherwise continue for plain args
  
                };
              }
  
              function condition() {
                return [expect(parsers.condition, 'expected condition')];
              }
            },
            arguments: function _arguments(prevArgs) {
              var argsComma = prevArgs || [];
              var argsSemiColon = [];
              var isSemiColonSeparated;
              var value;
              parserInput.save();
  
              while (true) {
                if (prevArgs) {
                  prevArgs = false;
                } else {
                  value = parsers.detachedRuleset() || this.assignment() || parsers.expression();
  
                  if (!value) {
                    break;
                  }
  
                  if (value.value && value.value.length == 1) {
                    value = value.value[0];
                  }
  
                  argsComma.push(value);
                }
  
                if (parserInput.$char(',')) {
                  continue;
                }
  
                if (parserInput.$char(';') || isSemiColonSeparated) {
                  isSemiColonSeparated = true;
                  value = argsComma.length < 1 ? argsComma[0] : new tree.Value(argsComma);
                  argsSemiColon.push(value);
                  argsComma = [];
                }
              }
  
              parserInput.forget();
              return isSemiColonSeparated ? argsSemiColon : argsComma;
            },
            literal: function literal() {
              return this.dimension() || this.color() || this.quoted() || this.unicodeDescriptor();
            },
            // Assignments are argument entities for calls.
            // They are present in ie filter properties as shown below.
            //
            //     filter: progid:DXImageTransform.Microsoft.Alpha( *opacity=50* )
            //
            assignment: function assignment() {
              var key;
              var value;
              parserInput.save();
              key = parserInput.$re(/^\w+(?=\s?=)/i);
  
              if (!key) {
                parserInput.restore();
                return;
              }
  
              if (!parserInput.$char('=')) {
                parserInput.restore();
                return;
              }
  
              value = parsers.entity();
  
              if (value) {
                parserInput.forget();
                return new tree.Assignment(key, value);
              } else {
                parserInput.restore();
              }
            },
            //
            // Parse url() tokens
            //
            // We use a specific rule for urls, because they don't really behave like
            // standard function calls. The difference is that the argument doesn't have
            // to be enclosed within a string, so it can't be parsed as an Expression.
            //
            url: function url() {
              var value;
              var index = parserInput.i;
              parserInput.autoCommentAbsorb = false;
  
              if (!parserInput.$str('url(')) {
                parserInput.autoCommentAbsorb = true;
                return;
              }
  
              value = this.quoted() || this.variable() || this.property() || parserInput.$re(/^(?:(?:\\[\(\)'"])|[^\(\)'"])+/) || '';
              parserInput.autoCommentAbsorb = true;
              expectChar(')');
              return new tree.URL(value.value != null || value instanceof tree.Variable || value instanceof tree.Property ? value : new tree.Anonymous(value, index), index, fileInfo);
            },
            //
            // A Variable entity, such as `@fink`, in
            //
            //     width: @fink + 2px
            //
            // We use a different parser for variable definitions,
            // see `parsers.variable`.
            //
            variable: function variable() {
              var ch;
              var name;
              var index = parserInput.i;
              parserInput.save();
  
              if (parserInput.currentChar() === '@' && (name = parserInput.$re(/^@@?[\w-]+/))) {
                ch = parserInput.currentChar();
  
                if (ch === '(' || ch === '[' && !parserInput.prevChar().match(/^\s/)) {
                  // this may be a VariableCall lookup
                  var result = parsers.variableCall(name);
  
                  if (result) {
                    parserInput.forget();
                    return result;
                  }
                }
  
                parserInput.forget();
                return new tree.Variable(name, index, fileInfo);
              }
  
              parserInput.restore();
            },
            // A variable entity using the protective {} e.g. @{var}
            variableCurly: function variableCurly() {
              var curly;
              var index = parserInput.i;
  
              if (parserInput.currentChar() === '@' && (curly = parserInput.$re(/^@\{([\w-]+)\}/))) {
                return new tree.Variable("@".concat(curly[1]), index, fileInfo);
              }
            },
            //
            // A Property accessor, such as `$color`, in
            //
            //     background-color: $color
            //
            property: function property() {
              var name;
              var index = parserInput.i;
  
              if (parserInput.currentChar() === '$' && (name = parserInput.$re(/^\$[\w-]+/))) {
                return new tree.Property(name, index, fileInfo);
              }
            },
            // A property entity useing the protective {} e.g. ${prop}
            propertyCurly: function propertyCurly() {
              var curly;
              var index = parserInput.i;
  
              if (parserInput.currentChar() === '$' && (curly = parserInput.$re(/^\$\{([\w-]+)\}/))) {
                return new tree.Property("$".concat(curly[1]), index, fileInfo);
              }
            },
            //
            // A Hexadecimal color
            //
            //     #4F3C2F
            //
            // `rgb` and `hsl` colors are parsed through the `entities.call` parser.
            //
            color: function color() {
              var rgb;
              parserInput.save();
  
              if (parserInput.currentChar() === '#' && (rgb = parserInput.$re(/^#([A-Fa-f0-9]{8}|[A-Fa-f0-9]{6}|[A-Fa-f0-9]{3,4})([\w.#\[])?/))) {
                if (!rgb[2]) {
                  parserInput.forget();
                  return new tree.Color(rgb[1], undefined, rgb[0]);
                }
              }
  
              parserInput.restore();
            },
            colorKeyword: function colorKeyword() {
              parserInput.save();
              var autoCommentAbsorb = parserInput.autoCommentAbsorb;
              parserInput.autoCommentAbsorb = false;
              var k = parserInput.$re(/^[_A-Za-z-][_A-Za-z0-9-]+/);
              parserInput.autoCommentAbsorb = autoCommentAbsorb;
  
              if (!k) {
                parserInput.forget();
                return;
              }
  
              parserInput.restore();
              var color = tree.Color.fromKeyword(k);
  
              if (color) {
                parserInput.$str(k);
                return color;
              }
            },
            //
            // A Dimension, that is, a number and a unit
            //
            //     0.5em 95%
            //
            dimension: function dimension() {
              if (parserInput.peekNotNumeric()) {
                return;
              }
  
              var value = parserInput.$re(/^([+-]?\d*\.?\d+)(%|[a-z_]+)?/i);
  
              if (value) {
                return new tree.Dimension(value[1], value[2]);
              }
            },
            //
            // A unicode descriptor, as is used in unicode-range
            //
            // U+0??  or U+00A1-00A9
            //
            unicodeDescriptor: function unicodeDescriptor() {
              var ud;
              ud = parserInput.$re(/^U\+[0-9a-fA-F?]+(\-[0-9a-fA-F?]+)?/);
  
              if (ud) {
                return new tree.UnicodeDescriptor(ud[0]);
              }
            },
            //
            // JavaScript code to be evaluated
            //
            //     `window.location.href`
            //
            javascript: function javascript() {
              var js;
              var index = parserInput.i;
              parserInput.save();
              var escape = parserInput.$char('~');
              var jsQuote = parserInput.$char('`');
  
              if (!jsQuote) {
                parserInput.restore();
                return;
              }
  
              js = parserInput.$re(/^[^`]*`/);
  
              if (js) {
                parserInput.forget();
                return new tree.JavaScript(js.substr(0, js.length - 1), Boolean(escape), index, fileInfo);
              }
  
              parserInput.restore('invalid javascript definition');
            }
          },
          //
          // The variable part of a variable definition. Used in the `rule` parser
          //
          //     @fink:
          //
          variable: function variable() {
            var name;
  
            if (parserInput.currentChar() === '@' && (name = parserInput.$re(/^(@[\w-]+)\s*:/))) {
              return name[1];
            }
          },
          //
          // Call a variable value to retrieve a detached ruleset
          // or a value from a detached ruleset's rules.
          //
          //     @fink();
          //     @fink;
          //     color: @fink[@color];
          //
          variableCall: function variableCall(parsedName) {
            var lookups;
            var important;
            var i = parserInput.i;
            var inValue = !!parsedName;
            var name = parsedName;
            parserInput.save();
  
            if (name || parserInput.currentChar() === '@' && (name = parserInput.$re(/^(@[\w-]+)(\(\s*\))?/))) {
              lookups = this.mixin.ruleLookups();
  
              if (!lookups && (inValue && parserInput.$str('()') !== '()' || name[2] !== '()')) {
                parserInput.restore('Missing \'[...]\' lookup in variable call');
                return;
              }
  
              if (!inValue) {
                name = name[1];
              }
  
              if (lookups && parsers.important()) {
                important = true;
              }
  
              var call = new tree.VariableCall(name, i, fileInfo);
  
              if (!inValue && parsers.end()) {
                parserInput.forget();
                return call;
              } else {
                parserInput.forget();
                return new tree.NamespaceValue(call, lookups, important, i, fileInfo);
              }
            }
  
            parserInput.restore();
          },
          //
          // extend syntax - used to extend selectors
          //
          extend: function extend(isRule) {
            var elements;
            var e;
            var index = parserInput.i;
            var option;
            var extendList;
            var extend;
  
            if (!parserInput.$str(isRule ? '&:extend(' : ':extend(')) {
              return;
            }
  
            do {
              option = null;
              elements = null;
  
              while (!(option = parserInput.$re(/^(all)(?=\s*(\)|,))/))) {
                e = this.element();
  
                if (!e) {
                  break;
                }
  
                if (elements) {
                  elements.push(e);
                } else {
                  elements = [e];
                }
              }
  
              option = option && option[1];
  
              if (!elements) {
                error('Missing target selector for :extend().');
              }
  
              extend = new tree.Extend(new tree.Selector(elements), option, index, fileInfo);
  
              if (extendList) {
                extendList.push(extend);
              } else {
                extendList = [extend];
              }
            } while (parserInput.$char(','));
  
            expect(/^\)/);
  
            if (isRule) {
              expect(/^;/);
            }
  
            return extendList;
          },
          //
          // extendRule - used in a rule to extend all the parent selectors
          //
          extendRule: function extendRule() {
            return this.extend(true);
          },
          //
          // Mixins
          //
          mixin: {
            //
            // A Mixin call, with an optional argument list
            //
            //     #mixins > .square(#fff);
            //     #mixins.square(#fff);
            //     .rounded(4px, black);
            //     .button;
            //
            // We can lookup / return a value using the lookup syntax:
            //
            //     color: #mixin.square(#fff)[@color];
            //
            // The `while` loop is there because mixins can be
            // namespaced, but we only support the child and descendant
            // selector for now.
            //
            call: function call(inValue, getLookup) {
              var s = parserInput.currentChar();
              var important = false;
              var lookups;
              var index = parserInput.i;
              var elements;
              var args;
              var hasParens;
  
              if (s !== '.' && s !== '#') {
                return;
              }
  
              parserInput.save(); // stop us absorbing part of an invalid selector
  
              elements = this.elements();
  
              if (elements) {
                if (parserInput.$char('(')) {
                  args = this.args(true).args;
                  expectChar(')');
                  hasParens = true;
                }
  
                if (getLookup !== false) {
                  lookups = this.ruleLookups();
                }
  
                if (getLookup === true && !lookups) {
                  parserInput.restore();
                  return;
                }
  
                if (inValue && !lookups && !hasParens) {
                  // This isn't a valid in-value mixin call
                  parserInput.restore();
                  return;
                }
  
                if (!inValue && parsers.important()) {
                  important = true;
                }
  
                if (inValue || parsers.end()) {
                  parserInput.forget();
                  var mixin = new tree.mixin.Call(elements, args, index, fileInfo, !lookups && important);
  
                  if (lookups) {
                    return new tree.NamespaceValue(mixin, lookups, important);
                  } else {
                    return mixin;
                  }
                }
              }
  
              parserInput.restore();
            },
  
            /**
             * Matching elements for mixins
             * (Start with . or # and can have > )
             */
            elements: function elements() {
              var elements;
              var e;
              var c;
              var elem;
              var elemIndex;
              var re = /^[#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/;
  
              while (true) {
                elemIndex = parserInput.i;
                e = parserInput.$re(re);
  
                if (!e) {
                  break;
                }
  
                elem = new tree.Element(c, e, false, elemIndex, fileInfo);
  
                if (elements) {
                  elements.push(elem);
                } else {
                  elements = [elem];
                }
  
                c = parserInput.$char('>');
              }
  
              return elements;
            },
            args: function args(isCall) {
              var entities = parsers.entities;
              var returner = {
                args: null,
                variadic: false
              };
              var expressions = [];
              var argsSemiColon = [];
              var argsComma = [];
              var isSemiColonSeparated;
              var expressionContainsNamed;
              var name;
              var nameLoop;
              var value;
              var arg;
              var expand;
              var hasSep = true;
              parserInput.save();
  
              while (true) {
                if (isCall) {
                  arg = parsers.detachedRuleset() || parsers.expression();
                } else {
                  parserInput.commentStore.length = 0;
  
                  if (parserInput.$str('...')) {
                    returner.variadic = true;
  
                    if (parserInput.$char(';') && !isSemiColonSeparated) {
                      isSemiColonSeparated = true;
                    }
  
                    (isSemiColonSeparated ? argsSemiColon : argsComma).push({
                      variadic: true
                    });
                    break;
                  }
  
                  arg = entities.variable() || entities.property() || entities.literal() || entities.keyword() || this.call(true);
                }
  
                if (!arg || !hasSep) {
                  break;
                }
  
                nameLoop = null;
  
                if (arg.throwAwayComments) {
                  arg.throwAwayComments();
                }
  
                value = arg;
                var val = null;
  
                if (isCall) {
                  // Variable
                  if (arg.value && arg.value.length == 1) {
                    val = arg.value[0];
                  }
                } else {
                  val = arg;
                }
  
                if (val && (val instanceof tree.Variable || val instanceof tree.Property)) {
                  if (parserInput.$char(':')) {
                    if (expressions.length > 0) {
                      if (isSemiColonSeparated) {
                        error('Cannot mix ; and , as delimiter types');
                      }
  
                      expressionContainsNamed = true;
                    }
  
                    value = parsers.detachedRuleset() || parsers.expression();
  
                    if (!value) {
                      if (isCall) {
                        error('could not understand value for named argument');
                      } else {
                        parserInput.restore();
                        returner.args = [];
                        return returner;
                      }
                    }
  
                    nameLoop = name = val.name;
                  } else if (parserInput.$str('...')) {
                    if (!isCall) {
                      returner.variadic = true;
  
                      if (parserInput.$char(';') && !isSemiColonSeparated) {
                        isSemiColonSeparated = true;
                      }
  
                      (isSemiColonSeparated ? argsSemiColon : argsComma).push({
                        name: arg.name,
                        variadic: true
                      });
                      break;
                    } else {
                      expand = true;
                    }
                  } else if (!isCall) {
                    name = nameLoop = val.name;
                    value = null;
                  }
                }
  
                if (value) {
                  expressions.push(value);
                }
  
                argsComma.push({
                  name: nameLoop,
                  value: value,
                  expand: expand
                });
  
                if (parserInput.$char(',')) {
                  hasSep = true;
                  continue;
                }
  
                hasSep = parserInput.$char(';') === ';';
  
                if (hasSep || isSemiColonSeparated) {
                  if (expressionContainsNamed) {
                    error('Cannot mix ; and , as delimiter types');
                  }
  
                  isSemiColonSeparated = true;
  
                  if (expressions.length > 1) {
                    value = new tree.Value(expressions);
                  }
  
                  argsSemiColon.push({
                    name: name,
                    value: value,
                    expand: expand
                  });
                  name = null;
                  expressions = [];
                  expressionContainsNamed = false;
                }
              }
  
              parserInput.forget();
              returner.args = isSemiColonSeparated ? argsSemiColon : argsComma;
              return returner;
            },
            //
            // A Mixin definition, with a list of parameters
            //
            //     .rounded (@radius: 2px, @color) {
            //        ...
            //     }
            //
            // Until we have a finer grained state-machine, we have to
            // do a look-ahead, to make sure we don't have a mixin call.
            // See the `rule` function for more information.
            //
            // We start by matching `.rounded (`, and then proceed on to
            // the argument list, which has optional default values.
            // We store the parameters in `params`, with a `value` key,
            // if there is a value, such as in the case of `@radius`.
            //
            // Once we've got our params list, and a closing `)`, we parse
            // the `{...}` block.
            //
            definition: function definition() {
              var name;
              var params = [];
              var match;
              var ruleset;
              var cond;
              var variadic = false;
  
              if (parserInput.currentChar() !== '.' && parserInput.currentChar() !== '#' || parserInput.peek(/^[^{]*\}/)) {
                return;
              }
  
              parserInput.save();
              match = parserInput.$re(/^([#.](?:[\w-]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+)\s*\(/);
  
              if (match) {
                name = match[1];
                var argInfo = this.args(false);
                params = argInfo.args;
                variadic = argInfo.variadic; // .mixincall("@{a}");
                // looks a bit like a mixin definition..
                // also
                // .mixincall(@a: {rule: set;});
                // so we have to be nice and restore
  
                if (!parserInput.$char(')')) {
                  parserInput.restore('Missing closing \')\'');
                  return;
                }
  
                parserInput.commentStore.length = 0;
  
                if (parserInput.$str('when')) {
                  // Guard
                  cond = expect(parsers.conditions, 'expected condition');
                }
  
                ruleset = parsers.block();
  
                if (ruleset) {
                  parserInput.forget();
                  return new tree.mixin.Definition(name, params, ruleset, cond, variadic);
                } else {
                  parserInput.restore();
                }
              } else {
                parserInput.forget();
              }
            },
            ruleLookups: function ruleLookups() {
              var rule;
              var lookups = [];
  
              if (parserInput.currentChar() !== '[') {
                return;
              }
  
              while (true) {
                parserInput.save();
                rule = this.lookupValue();
  
                if (!rule && rule !== '') {
                  parserInput.restore();
                  break;
                }
  
                lookups.push(rule);
                parserInput.forget();
              }
  
              if (lookups.length > 0) {
                return lookups;
              }
            },
            lookupValue: function lookupValue() {
              parserInput.save();
  
              if (!parserInput.$char('[')) {
                parserInput.restore();
                return;
              }
  
              var name = parserInput.$re(/^(?:[@$]{0,2})[_a-zA-Z0-9-]*/);
  
              if (!parserInput.$char(']')) {
                parserInput.restore();
                return;
              }
  
              if (name || name === '') {
                parserInput.forget();
                return name;
              }
  
              parserInput.restore();
            }
          },
          //
          // Entities are the smallest recognized token,
          // and can be found inside a rule's value.
          //
          entity: function entity() {
            var entities = this.entities;
            return this.comment() || entities.literal() || entities.variable() || entities.url() || entities.property() || entities.call() || entities.keyword() || this.mixin.call(true) || entities.javascript();
          },
          //
          // A Declaration terminator. Note that we use `peek()` to check for '}',
          // because the `block` rule will be expecting it, but we still need to make sure
          // it's there, if ';' was omitted.
          //
          end: function end() {
            return parserInput.$char(';') || parserInput.peek('}');
          },
          //
          // IE's alpha function
          //
          //     alpha(opacity=88)
          //
          ieAlpha: function ieAlpha() {
            var value; // http://jsperf.com/case-insensitive-regex-vs-strtolower-then-regex/18
  
            if (!parserInput.$re(/^opacity=/i)) {
              return;
            }
  
            value = parserInput.$re(/^\d+/);
  
            if (!value) {
              value = expect(parsers.entities.variable, 'Could not parse alpha');
              value = "@{".concat(value.name.slice(1), "}");
            }
  
            expectChar(')');
            return new tree.Quoted('', "alpha(opacity=".concat(value, ")"));
          },
          //
          // A Selector Element
          //
          //     div
          //     + h1
          //     #socks
          //     input[type="text"]
          //
          // Elements are the building blocks for Selectors,
          // they are made out of a `Combinator` (see combinator rule),
          // and an element name, such as a tag a class, or `*`.
          //
          element: function element() {
            var e;
            var c;
            var v;
            var index = parserInput.i;
            c = this.combinator();
            e = parserInput.$re(/^(?:\d+\.\d+|\d+)%/) || parserInput.$re(/^(?:[.#]?|:*)(?:[\w-]|[^\x00-\x9f]|\\(?:[A-Fa-f0-9]{1,6} ?|[^A-Fa-f0-9]))+/) || parserInput.$char('*') || parserInput.$char('&') || this.attribute() || parserInput.$re(/^\([^&()@]+\)/) || parserInput.$re(/^[\.#:](?=@)/) || this.entities.variableCurly();
  
            if (!e) {
              parserInput.save();
  
              if (parserInput.$char('(')) {
                if ((v = this.selector(false)) && parserInput.$char(')')) {
                  e = new tree.Paren(v);
                  parserInput.forget();
                } else {
                  parserInput.restore('Missing closing \')\'');
                }
              } else {
                parserInput.forget();
              }
            }
  
            if (e) {
              return new tree.Element(c, e, e instanceof tree.Variable, index, fileInfo);
            }
          },
          //
          // Combinators combine elements together, in a Selector.
          //
          // Because our parser isn't white-space sensitive, special care
          // has to be taken, when parsing the descendant combinator, ` `,
          // as it's an empty space. We have to check the previous character
          // in the input, to see if it's a ` ` character. More info on how
          // we deal with this in *combinator.js*.
          //
          combinator: function combinator() {
            var c = parserInput.currentChar();
  
            if (c === '/') {
              parserInput.save();
              var slashedCombinator = parserInput.$re(/^\/[a-z]+\//i);
  
              if (slashedCombinator) {
                parserInput.forget();
                return new tree.Combinator(slashedCombinator);
              }
  
              parserInput.restore();
            }
  
            if (c === '>' || c === '+' || c === '~' || c === '|' || c === '^') {
              parserInput.i++;
  
              if (c === '^' && parserInput.currentChar() === '^') {
                c = '^^';
                parserInput.i++;
              }
  
              while (parserInput.isWhitespace()) {
                parserInput.i++;
              }
  
              return new tree.Combinator(c);
            } else if (parserInput.isWhitespace(-1)) {
              return new tree.Combinator(' ');
            } else {
              return new tree.Combinator(null);
            }
          },
          //
          // A CSS Selector
          // with less extensions e.g. the ability to extend and guard
          //
          //     .class > div + h1
          //     li a:hover
          //
          // Selectors are made out of one or more Elements, see above.
          //
          selector: function selector(isLess) {
            var index = parserInput.i;
            var elements;
            var extendList;
            var c;
            var e;
            var allExtends;
            var when;
            var condition;
            isLess = isLess !== false;
  
            while (isLess && (extendList = this.extend()) || isLess && (when = parserInput.$str('when')) || (e = this.element())) {
              if (when) {
                condition = expect(this.conditions, 'expected condition');
              } else if (condition) {
                error('CSS guard can only be used at the end of selector');
              } else if (extendList) {
                if (allExtends) {
                  allExtends = allExtends.concat(extendList);
                } else {
                  allExtends = extendList;
                }
              } else {
                if (allExtends) {
                  error('Extend can only be used at the end of selector');
                }
  
                c = parserInput.currentChar();
  
                if (elements) {
                  elements.push(e);
                } else {
                  elements = [e];
                }
  
                e = null;
              }
  
              if (c === '{' || c === '}' || c === ';' || c === ',' || c === ')') {
                break;
              }
            }
  
            if (elements) {
              return new tree.Selector(elements, allExtends, condition, index, fileInfo);
            }
  
            if (allExtends) {
              error('Extend must be used to extend a selector, it cannot be used on its own');
            }
          },
          selectors: function selectors() {
            var s;
            var selectors;
  
            while (true) {
              s = this.selector();
  
              if (!s) {
                break;
              }
  
              if (selectors) {
                selectors.push(s);
              } else {
                selectors = [s];
              }
  
              parserInput.commentStore.length = 0;
  
              if (s.condition && selectors.length > 1) {
                error("Guards are only currently allowed on a single selector.");
              }
  
              if (!parserInput.$char(',')) {
                break;
              }
  
              if (s.condition) {
                error("Guards are only currently allowed on a single selector.");
              }
  
              parserInput.commentStore.length = 0;
            }
  
            return selectors;
          },
          attribute: function attribute() {
            if (!parserInput.$char('[')) {
              return;
            }
  
            var entities = this.entities;
            var key;
            var val;
            var op;
  
            if (!(key = entities.variableCurly())) {
              key = expect(/^(?:[_A-Za-z0-9-\*]*\|)?(?:[_A-Za-z0-9-]|\\.)+/);
            }
  
            op = parserInput.$re(/^[|~*$^]?=/);
  
            if (op) {
              val = entities.quoted() || parserInput.$re(/^[0-9]+%/) || parserInput.$re(/^[\w-]+/) || entities.variableCurly();
            }
  
            expectChar(']');
            return new tree.Attribute(key, op, val);
          },
          //
          // The `block` rule is used by `ruleset` and `mixin.definition`.
          // It's a wrapper around the `primary` rule, with added `{}`.
          //
          block: function block() {
            var content;
  
            if (parserInput.$char('{') && (content = this.primary()) && parserInput.$char('}')) {
              return content;
            }
          },
          blockRuleset: function blockRuleset() {
            var block = this.block();
  
            if (block) {
              block = new tree.Ruleset(null, block);
            }
  
            return block;
          },
          detachedRuleset: function detachedRuleset() {
            var argInfo;
            var params;
            var variadic;
            parserInput.save();
  
            if (parserInput.$re(/^[.#]\(/)) {
              /**
               * DR args currently only implemented for each() function, and not 
               * yet settable as `@dr: #(@arg) {}`
               * This should be done when DRs are merged with mixins.
               * See: https://github.com/less/less-meta/issues/16
               */
              argInfo = this.mixin.args(false);
              params = argInfo.args;
              variadic = argInfo.variadic;
  
              if (!parserInput.$char(')')) {
                parserInput.restore();
                return;
              }
            }
  
            var blockRuleset = this.blockRuleset();
  
            if (blockRuleset) {
              parserInput.forget();
  
              if (params) {
                return new tree.mixin.Definition(null, params, blockRuleset, null, variadic);
              }
  
              return new tree.DetachedRuleset(blockRuleset);
            }
  
            parserInput.restore();
          },
          //
          // div, .class, body > p {...}
          //
          ruleset: function ruleset() {
            var selectors;
            var rules;
            var debugInfo;
            parserInput.save();
  
            if (context.dumpLineNumbers) {
              debugInfo = getDebugInfo(parserInput.i);
            }
  
            selectors = this.selectors();
  
            if (selectors && (rules = this.block())) {
              parserInput.forget();
              var ruleset = new tree.Ruleset(selectors, rules, context.strictImports);
  
              if (context.dumpLineNumbers) {
                ruleset.debugInfo = debugInfo;
              }
  
              return ruleset;
            } else {
              parserInput.restore();
            }
          },
          declaration: function declaration() {
            var name;
            var value;
            var index = parserInput.i;
            var hasDR;
            var c = parserInput.currentChar();
            var important;
            var merge;
            var isVariable;
  
            if (c === '.' || c === '#' || c === '&' || c === ':') {
              return;
            }
  
            parserInput.save();
            name = this.variable() || this.ruleProperty();
  
            if (name) {
              isVariable = typeof name === 'string';
  
              if (isVariable) {
                value = this.detachedRuleset();
  
                if (value) {
                  hasDR = true;
                }
              }
  
              parserInput.commentStore.length = 0;
  
              if (!value) {
                // a name returned by this.ruleProperty() is always an array of the form:
                // [string-1, ..., string-n, ""] or [string-1, ..., string-n, "+"]
                // where each item is a tree.Keyword or tree.Variable
                merge = !isVariable && name.length > 1 && name.pop().value; // Custom property values get permissive parsing
  
                if (name[0].value && name[0].value.slice(0, 2) === '--') {
                  value = this.permissiveValue();
                } // Try to store values as anonymous
                // If we need the value later we'll re-parse it in ruleset.parseValue
                else {
                    value = this.anonymousValue();
                  }
  
                if (value) {
                  parserInput.forget(); // anonymous values absorb the end ';' which is required for them to work
  
                  return new tree.Declaration(name, value, false, merge, index, fileInfo);
                }
  
                if (!value) {
                  value = this.value();
                }
  
                if (value) {
                  important = this.important();
                } else if (isVariable) {
                  // As a last resort, try permissiveValue
                  value = this.permissiveValue();
                }
              }
  
              if (value && (this.end() || hasDR)) {
                parserInput.forget();
                return new tree.Declaration(name, value, important, merge, index, fileInfo);
              } else {
                parserInput.restore();
              }
            } else {
              parserInput.restore();
            }
          },
          anonymousValue: function anonymousValue() {
            var index = parserInput.i;
            var match = parserInput.$re(/^([^.#@\$+\/'"*`(;{}-]*);/);
  
            if (match) {
              return new tree.Anonymous(match[1], index);
            }
          },
  
          /**
           * Used for custom properties, at-rules, and variables (as fallback)
           * Parses almost anything inside of {} [] () "" blocks
           * until it reaches outer-most tokens.
           * 
           * First, it will try to parse comments and entities to reach
           * the end. This is mostly like the Expression parser except no
           * math is allowed.
           */
          permissiveValue: function permissiveValue(untilTokens) {
            var i;
            var e;
            var done;
            var value;
            var tok = untilTokens || ';';
            var index = parserInput.i;
            var result = [];
  
            function testCurrentChar() {
              var char = parserInput.currentChar();
  
              if (typeof tok === 'string') {
                return char === tok;
              } else {
                return tok.test(char);
              }
            }
  
            if (testCurrentChar()) {
              return;
            }
  
            value = [];
  
            do {
              e = this.comment();
  
              if (e) {
                value.push(e);
                continue;
              }
  
              e = this.entity();
  
              if (e) {
                value.push(e);
              }
            } while (e);
  
            done = testCurrentChar();
  
            if (value.length > 0) {
              value = new tree.Expression(value);
  
              if (done) {
                return value;
              } else {
                result.push(value);
              } // Preserve space before $parseUntil as it will not
  
  
              if (parserInput.prevChar() === ' ') {
                result.push(new tree.Anonymous(' ', index));
              }
            }
  
            parserInput.save();
            value = parserInput.$parseUntil(tok);
  
            if (value) {
              if (typeof value === 'string') {
                error("Expected '".concat(value, "'"), 'Parse');
              }
  
              if (value.length === 1 && value[0] === ' ') {
                parserInput.forget();
                return new tree.Anonymous('', index);
              }
  
              var item;
  
              for (i = 0; i < value.length; i++) {
                item = value[i];
  
                if (Array.isArray(item)) {
                  // Treat actual quotes as normal quoted values
                  result.push(new tree.Quoted(item[0], item[1], true, index, fileInfo));
                } else {
                  if (i === value.length - 1) {
                    item = item.trim();
                  } // Treat like quoted values, but replace vars like unquoted expressions
  
  
                  var quote = new tree.Quoted('\'', item, true, index, fileInfo);
                  quote.variableRegex = /@([\w-]+)/g;
                  quote.propRegex = /\$([\w-]+)/g;
                  result.push(quote);
                }
              }
  
              parserInput.forget();
              return new tree.Expression(result, true);
            }
  
            parserInput.restore();
          },
          //
          // An @import atrule
          //
          //     @import "lib";
          //
          // Depending on our environment, importing is done differently:
          // In the browser, it's an XHR request, in Node, it would be a
          // file-system operation. The function used for importing is
          // stored in `import`, which we pass to the Import constructor.
          //
          'import': function _import() {
            var path;
            var features;
            var index = parserInput.i;
            var dir = parserInput.$re(/^@import?\s+/);
  
            if (dir) {
              var options = (dir ? this.importOptions() : null) || {};
  
              if (path = this.entities.quoted() || this.entities.url()) {
                features = this.mediaFeatures();
  
                if (!parserInput.$char(';')) {
                  parserInput.i = index;
                  error('missing semi-colon or unrecognised media features on import');
                }
  
                features = features && new tree.Value(features);
                return new tree.Import(path, features, options, index, fileInfo);
              } else {
                parserInput.i = index;
                error('malformed import statement');
              }
            }
          },
          importOptions: function importOptions() {
            var o;
            var options = {};
            var optionName;
            var value; // list of options, surrounded by parens
  
            if (!parserInput.$char('(')) {
              return null;
            }
  
            do {
              o = this.importOption();
  
              if (o) {
                optionName = o;
                value = true;
  
                switch (optionName) {
                  case 'css':
                    optionName = 'less';
                    value = false;
                    break;
  
                  case 'once':
                    optionName = 'multiple';
                    value = false;
                    break;
                }
  
                options[optionName] = value;
  
                if (!parserInput.$char(',')) {
                  break;
                }
              }
            } while (o);
  
            expectChar(')');
            return options;
          },
          importOption: function importOption() {
            var opt = parserInput.$re(/^(less|css|multiple|once|inline|reference|optional)/);
  
            if (opt) {
              return opt[1];
            }
          },
          mediaFeature: function mediaFeature() {
            var entities = this.entities;
            var nodes = [];
            var e;
            var p;
            parserInput.save();
  
            do {
              e = entities.keyword() || entities.variable() || entities.mixinLookup();
  
              if (e) {
                nodes.push(e);
              } else if (parserInput.$char('(')) {
                p = this.property();
                e = this.value();
  
                if (parserInput.$char(')')) {
                  if (p && e) {
                    nodes.push(new tree.Paren(new tree.Declaration(p, e, null, null, parserInput.i, fileInfo, true)));
                  } else if (e) {
                    nodes.push(new tree.Paren(e));
                  } else {
                    error('badly formed media feature definition');
                  }
                } else {
                  error('Missing closing \')\'', 'Parse');
                }
              }
            } while (e);
  
            parserInput.forget();
  
            if (nodes.length > 0) {
              return new tree.Expression(nodes);
            }
          },
          mediaFeatures: function mediaFeatures() {
            var entities = this.entities;
            var features = [];
            var e;
  
            do {
              e = this.mediaFeature();
  
              if (e) {
                features.push(e);
  
                if (!parserInput.$char(',')) {
                  break;
                }
              } else {
                e = entities.variable() || entities.mixinLookup();
  
                if (e) {
                  features.push(e);
  
                  if (!parserInput.$char(',')) {
                    break;
                  }
                }
              }
            } while (e);
  
            return features.length > 0 ? features : null;
          },
          media: function media() {
            var features;
            var rules;
            var media;
            var debugInfo;
            var index = parserInput.i;
  
            if (context.dumpLineNumbers) {
              debugInfo = getDebugInfo(index);
            }
  
            parserInput.save();
  
            if (parserInput.$str('@media')) {
              features = this.mediaFeatures();
              rules = this.block();
  
              if (!rules) {
                error('media definitions require block statements after any features');
              }
  
              parserInput.forget();
              media = new tree.Media(rules, features, index, fileInfo);
  
              if (context.dumpLineNumbers) {
                media.debugInfo = debugInfo;
              }
  
              return media;
            }
  
            parserInput.restore();
          },
          //
          // A @plugin directive, used to import plugins dynamically.
          //
          //     @plugin (args) "lib";
          //
          plugin: function plugin() {
            var path;
            var args;
            var options;
            var index = parserInput.i;
            var dir = parserInput.$re(/^@plugin?\s+/);
  
            if (dir) {
              args = this.pluginArgs();
  
              if (args) {
                options = {
                  pluginArgs: args,
                  isPlugin: true
                };
              } else {
                options = {
                  isPlugin: true
                };
              }
  
              if (path = this.entities.quoted() || this.entities.url()) {
                if (!parserInput.$char(';')) {
                  parserInput.i = index;
                  error('missing semi-colon on @plugin');
                }
  
                return new tree.Import(path, null, options, index, fileInfo);
              } else {
                parserInput.i = index;
                error('malformed @plugin statement');
              }
            }
          },
          pluginArgs: function pluginArgs() {
            // list of options, surrounded by parens
            parserInput.save();
  
            if (!parserInput.$char('(')) {
              parserInput.restore();
              return null;
            }
  
            var args = parserInput.$re(/^\s*([^\);]+)\)\s*/);
  
            if (args[1]) {
              parserInput.forget();
              return args[1].trim();
            } else {
              parserInput.restore();
              return null;
            }
          },
          //
          // A CSS AtRule
          //
          //     @charset "utf-8";
          //
          atrule: function atrule() {
            var index = parserInput.i;
            var name;
            var value;
            var rules;
            var nonVendorSpecificName;
            var hasIdentifier;
            var hasExpression;
            var hasUnknown;
            var hasBlock = true;
            var isRooted = true;
  
            if (parserInput.currentChar() !== '@') {
              return;
            }
  
            value = this['import']() || this.plugin() || this.media();
  
            if (value) {
              return value;
            }
  
            parserInput.save();
            name = parserInput.$re(/^@[a-z-]+/);
  
            if (!name) {
              return;
            }
  
            nonVendorSpecificName = name;
  
            if (name.charAt(1) == '-' && name.indexOf('-', 2) > 0) {
              nonVendorSpecificName = "@".concat(name.slice(name.indexOf('-', 2) + 1));
            }
  
            switch (nonVendorSpecificName) {
              case '@charset':
                hasIdentifier = true;
                hasBlock = false;
                break;
  
              case '@namespace':
                hasExpression = true;
                hasBlock = false;
                break;
  
              case '@keyframes':
              case '@counter-style':
                hasIdentifier = true;
                break;
  
              case '@document':
              case '@supports':
                hasUnknown = true;
                isRooted = false;
                break;
  
              default:
                hasUnknown = true;
                break;
            }
  
            parserInput.commentStore.length = 0;
  
            if (hasIdentifier) {
              value = this.entity();
  
              if (!value) {
                error("expected ".concat(name, " identifier"));
              }
            } else if (hasExpression) {
              value = this.expression();
  
              if (!value) {
                error("expected ".concat(name, " expression"));
              }
            } else if (hasUnknown) {
              value = this.permissiveValue(/^[{;]/);
              hasBlock = parserInput.currentChar() === '{';
  
              if (!value) {
                if (!hasBlock && parserInput.currentChar() !== ';') {
                  error("".concat(name, " rule is missing block or ending semi-colon"));
                }
              } else if (!value.value) {
                value = null;
              }
            }
  
            if (hasBlock) {
              rules = this.blockRuleset();
            }
  
            if (rules || !hasBlock && value && parserInput.$char(';')) {
              parserInput.forget();
              return new tree.AtRule(name, value, rules, index, fileInfo, context.dumpLineNumbers ? getDebugInfo(index) : null, isRooted);
            }
  
            parserInput.restore('at-rule options not recognised');
          },
          //
          // A Value is a comma-delimited list of Expressions
          //
          //     font-family: Baskerville, Georgia, serif;
          //
          // In a Rule, a Value represents everything after the `:`,
          // and before the `;`.
          //
          value: function value() {
            var e;
            var expressions = [];
            var index = parserInput.i;
  
            do {
              e = this.expression();
  
              if (e) {
                expressions.push(e);
  
                if (!parserInput.$char(',')) {
                  break;
                }
              }
            } while (e);
  
            if (expressions.length > 0) {
              return new tree.Value(expressions, index);
            }
          },
          important: function important() {
            if (parserInput.currentChar() === '!') {
              return parserInput.$re(/^! *important/);
            }
          },
          sub: function sub() {
            var a;
            var e;
            parserInput.save();
  
            if (parserInput.$char('(')) {
              a = this.addition();
  
              if (a && parserInput.$char(')')) {
                parserInput.forget();
                e = new tree.Expression([a]);
                e.parens = true;
                return e;
              }
  
              parserInput.restore('Expected \')\'');
              return;
            }
  
            parserInput.restore();
          },
          multiplication: function multiplication() {
            var m;
            var a;
            var op;
            var operation;
            var isSpaced;
            m = this.operand();
  
            if (m) {
              isSpaced = parserInput.isWhitespace(-1);
  
              while (true) {
                if (parserInput.peek(/^\/[*\/]/)) {
                  break;
                }
  
                parserInput.save();
                op = parserInput.$char('/') || parserInput.$char('*') || parserInput.$str('./');
  
                if (!op) {
                  parserInput.forget();
                  break;
                }
  
                a = this.operand();
  
                if (!a) {
                  parserInput.restore();
                  break;
                }
  
                parserInput.forget();
                m.parensInOp = true;
                a.parensInOp = true;
                operation = new tree.Operation(op, [operation || m, a], isSpaced);
                isSpaced = parserInput.isWhitespace(-1);
              }
  
              return operation || m;
            }
          },
          addition: function addition() {
            var m;
            var a;
            var op;
            var operation;
            var isSpaced;
            m = this.multiplication();
  
            if (m) {
              isSpaced = parserInput.isWhitespace(-1);
  
              while (true) {
                op = parserInput.$re(/^[-+]\s+/) || !isSpaced && (parserInput.$char('+') || parserInput.$char('-'));
  
                if (!op) {
                  break;
                }
  
                a = this.multiplication();
  
                if (!a) {
                  break;
                }
  
                m.parensInOp = true;
                a.parensInOp = true;
                operation = new tree.Operation(op, [operation || m, a], isSpaced);
                isSpaced = parserInput.isWhitespace(-1);
              }
  
              return operation || m;
            }
          },
          conditions: function conditions() {
            var a;
            var b;
            var index = parserInput.i;
            var condition;
            a = this.condition(true);
  
            if (a) {
              while (true) {
                if (!parserInput.peek(/^,\s*(not\s*)?\(/) || !parserInput.$char(',')) {
                  break;
                }
  
                b = this.condition(true);
  
                if (!b) {
                  break;
                }
  
                condition = new tree.Condition('or', condition || a, b, index);
              }
  
              return condition || a;
            }
          },
          condition: function condition(needsParens) {
            var result;
            var logical;
            var next;
  
            function or() {
              return parserInput.$str('or');
            }
  
            result = this.conditionAnd(needsParens);
  
            if (!result) {
              return;
            }
  
            logical = or();
  
            if (logical) {
              next = this.condition(needsParens);
  
              if (next) {
                result = new tree.Condition(logical, result, next);
              } else {
                return;
              }
            }
  
            return result;
          },
          conditionAnd: function conditionAnd(needsParens) {
            var result;
            var logical;
            var next;
            var self = this;
  
            function insideCondition() {
              var cond = self.negatedCondition(needsParens) || self.parenthesisCondition(needsParens);
  
              if (!cond && !needsParens) {
                return self.atomicCondition(needsParens);
              }
  
              return cond;
            }
  
            function and() {
              return parserInput.$str('and');
            }
  
            result = insideCondition();
  
            if (!result) {
              return;
            }
  
            logical = and();
  
            if (logical) {
              next = this.conditionAnd(needsParens);
  
              if (next) {
                result = new tree.Condition(logical, result, next);
              } else {
                return;
              }
            }
  
            return result;
          },
          negatedCondition: function negatedCondition(needsParens) {
            if (parserInput.$str('not')) {
              var result = this.parenthesisCondition(needsParens);
  
              if (result) {
                result.negate = !result.negate;
              }
  
              return result;
            }
          },
          parenthesisCondition: function parenthesisCondition(needsParens) {
            function tryConditionFollowedByParenthesis(me) {
              var body;
              parserInput.save();
              body = me.condition(needsParens);
  
              if (!body) {
                parserInput.restore();
                return;
              }
  
              if (!parserInput.$char(')')) {
                parserInput.restore();
                return;
              }
  
              parserInput.forget();
              return body;
            }
  
            var body;
            parserInput.save();
  
            if (!parserInput.$str('(')) {
              parserInput.restore();
              return;
            }
  
            body = tryConditionFollowedByParenthesis(this);
  
            if (body) {
              parserInput.forget();
              return body;
            }
  
            body = this.atomicCondition(needsParens);
  
            if (!body) {
              parserInput.restore();
              return;
            }
  
            if (!parserInput.$char(')')) {
              parserInput.restore("expected ')' got '".concat(parserInput.currentChar(), "'"));
              return;
            }
  
            parserInput.forget();
            return body;
          },
          atomicCondition: function atomicCondition(needsParens) {
            var entities = this.entities;
            var index = parserInput.i;
            var a;
            var b;
            var c;
            var op;
  
            function cond() {
              return this.addition() || entities.keyword() || entities.quoted() || entities.mixinLookup();
            }
  
            cond = cond.bind(this);
            a = cond();
  
            if (a) {
              if (parserInput.$char('>')) {
                if (parserInput.$char('=')) {
                  op = '>=';
                } else {
                  op = '>';
                }
              } else if (parserInput.$char('<')) {
                if (parserInput.$char('=')) {
                  op = '<=';
                } else {
                  op = '<';
                }
              } else if (parserInput.$char('=')) {
                if (parserInput.$char('>')) {
                  op = '=>';
                } else if (parserInput.$char('<')) {
                  op = '=<';
                } else {
                  op = '=';
                }
              }
  
              if (op) {
                b = cond();
  
                if (b) {
                  c = new tree.Condition(op, a, b, index, false);
                } else {
                  error('expected expression');
                }
              } else {
                c = new tree.Condition('=', a, new tree.Keyword('true'), index, false);
              }
  
              return c;
            }
          },
          //
          // An operand is anything that can be part of an operation,
          // such as a Color, or a Variable
          //
          operand: function operand() {
            var entities = this.entities;
            var negate;
  
            if (parserInput.peek(/^-[@\$\(]/)) {
              negate = parserInput.$char('-');
            }
  
            var o = this.sub() || entities.dimension() || entities.color() || entities.variable() || entities.property() || entities.call() || entities.quoted(true) || entities.colorKeyword() || entities.mixinLookup();
  
            if (negate) {
              o.parensInOp = true;
              o = new tree.Negative(o);
            }
  
            return o;
          },
          //
          // Expressions either represent mathematical operations,
          // or white-space delimited Entities.
          //
          //     1px solid black
          //     @var * 2
          //
          expression: function expression() {
            var entities = [];
            var e;
            var delim;
            var index = parserInput.i;
  
            do {
              e = this.comment();
  
              if (e) {
                entities.push(e);
                continue;
              }
  
              e = this.addition() || this.entity();
  
              if (e) {
                entities.push(e); // operations do not allow keyword "/" dimension (e.g. small/20px) so we support that here
  
                if (!parserInput.peek(/^\/[\/*]/)) {
                  delim = parserInput.$char('/');
  
                  if (delim) {
                    entities.push(new tree.Anonymous(delim, index));
                  }
                }
              }
            } while (e);
  
            if (entities.length > 0) {
              return new tree.Expression(entities);
            }
          },
          property: function property() {
            var name = parserInput.$re(/^(\*?-?[_a-zA-Z0-9-]+)\s*:/);
  
            if (name) {
              return name[1];
            }
          },
          ruleProperty: function ruleProperty() {
            var name = [];
            var index = [];
            var s;
            var k;
            parserInput.save();
            var simpleProperty = parserInput.$re(/^([_a-zA-Z0-9-]+)\s*:/);
  
            if (simpleProperty) {
              name = [new tree.Keyword(simpleProperty[1])];
              parserInput.forget();
              return name;
            }
  
            function match(re) {
              var i = parserInput.i;
              var chunk = parserInput.$re(re);
  
              if (chunk) {
                index.push(i);
                return name.push(chunk[1]);
              }
            }
  
            match(/^(\*?)/);
  
            while (true) {
              if (!match(/^((?:[\w-]+)|(?:[@\$]\{[\w-]+\}))/)) {
                break;
              }
            }
  
            if (name.length > 1 && match(/^((?:\+_|\+)?)\s*:/)) {
              parserInput.forget(); // at last, we have the complete match now. move forward,
              // convert name particles to tree objects and return:
  
              if (name[0] === '') {
                name.shift();
                index.shift();
              }
  
              for (k = 0; k < name.length; k++) {
                s = name[k];
                name[k] = s.charAt(0) !== '@' && s.charAt(0) !== '$' ? new tree.Keyword(s) : s.charAt(0) === '@' ? new tree.Variable("@".concat(s.slice(2, -1)), index[k], fileInfo) : new tree.Property("$".concat(s.slice(2, -1)), index[k], fileInfo);
              }
  
              return name;
            }
  
            parserInput.restore();
          }
        }
      };
    };
  
    Parser.serializeVars = function (vars) {
      var s = '';
  
      for (var name in vars) {
        if (Object.hasOwnProperty.call(vars, name)) {
          var value = vars[name];
          s += "".concat((name[0] === '@' ? '' : '@') + name, ": ").concat(value).concat(String(value).slice(-1) === ';' ? '' : ';');
        }
      }
  
      return s;
    };
  
    function boolean(condition) {
      return condition ? Keyword.True : Keyword.False;
    }
  
    function If(condition, trueValue, falseValue) {
      return condition ? trueValue : falseValue || new Anonymous();
    }
  
    var boolean$1 = {
      boolean: boolean,
      'if': If
    };
  
    var colorFunctions;
  
    function clamp$1(val) {
      return Math.min(1, Math.max(0, val));
    }
  
    function hsla(origColor, hsl) {
      var color = colorFunctions.hsla(hsl.h, hsl.s, hsl.l, hsl.a);
  
      if (color) {
        if (origColor.value && /^(rgb|hsl)/.test(origColor.value)) {
          color.value = origColor.value;
        } else {
          color.value = 'rgb';
        }
  
        return color;
      }
    }
  
    function toHSL(color) {
      if (color.toHSL) {
        return color.toHSL();
      } else {
        throw new Error('Argument cannot be evaluated to a color');
      }
    }
  
    function toHSV(color) {
      if (color.toHSV) {
        return color.toHSV();
      } else {
        throw new Error('Argument cannot be evaluated to a color');
      }
    }
  
    function number(n) {
      if (n instanceof Dimension) {
        return parseFloat(n.unit.is('%') ? n.value / 100 : n.value);
      } else if (typeof n === 'number') {
        return n;
      } else {
        throw {
          type: 'Argument',
          message: 'color functions take numbers as parameters'
        };
      }
    }
  
    function scaled(n, size) {
      if (n instanceof Dimension && n.unit.is('%')) {
        return parseFloat(n.value * size / 100);
      } else {
        return number(n);
      }
    }
  
    colorFunctions = {
      rgb: function rgb(r, g, b) {
        var color = colorFunctions.rgba(r, g, b, 1.0);
  
        if (color) {
          color.value = 'rgb';
          return color;
        }
      },
      rgba: function rgba(r, g, b, a) {
        try {
          if (r instanceof Color) {
            if (g) {
              a = number(g);
            } else {
              a = r.alpha;
            }
  
            return new Color(r.rgb, a, 'rgba');
          }
  
          var rgb = [r, g, b].map(function (c) {
            return scaled(c, 255);
          });
          a = number(a);
          return new Color(rgb, a, 'rgba');
        } catch (e) {}
      },
      hsl: function hsl(h, s, l) {
        var color = colorFunctions.hsla(h, s, l, 1.0);
  
        if (color) {
          color.value = 'hsl';
          return color;
        }
      },
      hsla: function hsla(h, s, l, a) {
        try {
          var hue = function hue(h) {
            h = h < 0 ? h + 1 : h > 1 ? h - 1 : h;
  
            if (h * 6 < 1) {
              return m1 + (m2 - m1) * h * 6;
            } else if (h * 2 < 1) {
              return m2;
            } else if (h * 3 < 2) {
              return m1 + (m2 - m1) * (2 / 3 - h) * 6;
            } else {
              return m1;
            }
          };
  
          if (h instanceof Color) {
            if (s) {
              a = number(s);
            } else {
              a = h.alpha;
            }
  
            return new Color(h.rgb, a, 'hsla');
          }
  
          var m1;
          var m2;
          h = number(h) % 360 / 360;
          s = clamp$1(number(s));
          l = clamp$1(number(l));
          a = clamp$1(number(a));
          m2 = l <= 0.5 ? l * (s + 1) : l + s - l * s;
          m1 = l * 2 - m2;
          var rgb = [hue(h + 1 / 3) * 255, hue(h) * 255, hue(h - 1 / 3) * 255];
          a = number(a);
          return new Color(rgb, a, 'hsla');
        } catch (e) {}
      },
      hsv: function hsv(h, s, v) {
        return colorFunctions.hsva(h, s, v, 1.0);
      },
      hsva: function hsva(h, s, v, a) {
        h = number(h) % 360 / 360 * 360;
        s = number(s);
        v = number(v);
        a = number(a);
        var i;
        var f;
        i = Math.floor(h / 60 % 6);
        f = h / 60 - i;
        var vs = [v, v * (1 - s), v * (1 - f * s), v * (1 - (1 - f) * s)];
        var perm = [[0, 3, 1], [2, 0, 1], [1, 0, 3], [1, 2, 0], [3, 1, 0], [0, 1, 2]];
        return colorFunctions.rgba(vs[perm[i][0]] * 255, vs[perm[i][1]] * 255, vs[perm[i][2]] * 255, a);
      },
      hue: function hue(color) {
        return new Dimension(toHSL(color).h);
      },
      saturation: function saturation(color) {
        return new Dimension(toHSL(color).s * 100, '%');
      },
      lightness: function lightness(color) {
        return new Dimension(toHSL(color).l * 100, '%');
      },
      hsvhue: function hsvhue(color) {
        return new Dimension(toHSV(color).h);
      },
      hsvsaturation: function hsvsaturation(color) {
        return new Dimension(toHSV(color).s * 100, '%');
      },
      hsvvalue: function hsvvalue(color) {
        return new Dimension(toHSV(color).v * 100, '%');
      },
      red: function red(color) {
        return new Dimension(color.rgb[0]);
      },
      green: function green(color) {
        return new Dimension(color.rgb[1]);
      },
      blue: function blue(color) {
        return new Dimension(color.rgb[2]);
      },
      alpha: function alpha(color) {
        return new Dimension(toHSL(color).a);
      },
      luma: function luma(color) {
        return new Dimension(color.luma() * color.alpha * 100, '%');
      },
      luminance: function luminance(color) {
        var luminance = 0.2126 * color.rgb[0] / 255 + 0.7152 * color.rgb[1] / 255 + 0.0722 * color.rgb[2] / 255;
        return new Dimension(luminance * color.alpha * 100, '%');
      },
      saturate: function saturate(color, amount, method) {
        // filter: saturate(3.2);
        // should be kept as is, so check for color
        if (!color.rgb) {
          return null;
        }
  
        var hsl = toHSL(color);
  
        if (typeof method !== 'undefined' && method.value === 'relative') {
          hsl.s += hsl.s * amount.value / 100;
        } else {
          hsl.s += amount.value / 100;
        }
  
        hsl.s = clamp$1(hsl.s);
        return hsla(color, hsl);
      },
      desaturate: function desaturate(color, amount, method) {
        var hsl = toHSL(color);
  
        if (typeof method !== 'undefined' && method.value === 'relative') {
          hsl.s -= hsl.s * amount.value / 100;
        } else {
          hsl.s -= amount.value / 100;
        }
  
        hsl.s = clamp$1(hsl.s);
        return hsla(color, hsl);
      },
      lighten: function lighten(color, amount, method) {
        var hsl = toHSL(color);
  
        if (typeof method !== 'undefined' && method.value === 'relative') {
          hsl.l += hsl.l * amount.value / 100;
        } else {
          hsl.l += amount.value / 100;
        }
  
        hsl.l = clamp$1(hsl.l);
        return hsla(color, hsl);
      },
      darken: function darken(color, amount, method) {
        var hsl = toHSL(color);
  
        if (typeof method !== 'undefined' && method.value === 'relative') {
          hsl.l -= hsl.l * amount.value / 100;
        } else {
          hsl.l -= amount.value / 100;
        }
  
        hsl.l = clamp$1(hsl.l);
        return hsla(color, hsl);
      },
      fadein: function fadein(color, amount, method) {
        var hsl = toHSL(color);
  
        if (typeof method !== 'undefined' && method.value === 'relative') {
          hsl.a += hsl.a * amount.value / 100;
        } else {
          hsl.a += amount.value / 100;
        }
  
        hsl.a = clamp$1(hsl.a);
        return hsla(color, hsl);
      },
      fadeout: function fadeout(color, amount, method) {
        var hsl = toHSL(color);
  
        if (typeof method !== 'undefined' && method.value === 'relative') {
          hsl.a -= hsl.a * amount.value / 100;
        } else {
          hsl.a -= amount.value / 100;
        }
  
        hsl.a = clamp$1(hsl.a);
        return hsla(color, hsl);
      },
      fade: function fade(color, amount) {
        var hsl = toHSL(color);
        hsl.a = amount.value / 100;
        hsl.a = clamp$1(hsl.a);
        return hsla(color, hsl);
      },
      spin: function spin(color, amount) {
        var hsl = toHSL(color);
        var hue = (hsl.h + amount.value) % 360;
        hsl.h = hue < 0 ? 360 + hue : hue;
        return hsla(color, hsl);
      },
      //
      // Copyright (c) 2006-2009 Hampton Catlin, Natalie Weizenbaum, and Chris Eppstein
      // http://sass-lang.com
      //
      mix: function mix(color1, color2, weight) {
        if (!weight) {
          weight = new Dimension(50);
        }
  
        var p = weight.value / 100.0;
        var w = p * 2 - 1;
        var a = toHSL(color1).a - toHSL(color2).a;
        var w1 = ((w * a == -1 ? w : (w + a) / (1 + w * a)) + 1) / 2.0;
        var w2 = 1 - w1;
        var rgb = [color1.rgb[0] * w1 + color2.rgb[0] * w2, color1.rgb[1] * w1 + color2.rgb[1] * w2, color1.rgb[2] * w1 + color2.rgb[2] * w2];
        var alpha = color1.alpha * p + color2.alpha * (1 - p);
        return new Color(rgb, alpha);
      },
      greyscale: function greyscale(color) {
        return colorFunctions.desaturate(color, new Dimension(100));
      },
      contrast: function contrast(color, dark, light, threshold) {
        // filter: contrast(3.2);
        // should be kept as is, so check for color
        if (!color.rgb) {
          return null;
        }
  
        if (typeof light === 'undefined') {
          light = colorFunctions.rgba(255, 255, 255, 1.0);
        }
  
        if (typeof dark === 'undefined') {
          dark = colorFunctions.rgba(0, 0, 0, 1.0);
        } // Figure out which is actually light and dark:
  
  
        if (dark.luma() > light.luma()) {
          var t = light;
          light = dark;
          dark = t;
        }
  
        if (typeof threshold === 'undefined') {
          threshold = 0.43;
        } else {
          threshold = number(threshold);
        }
  
        if (color.luma() < threshold) {
          return light;
        } else {
          return dark;
        }
      },
      // Changes made in 2.7.0 - Reverted in 3.0.0
      // contrast: function (color, color1, color2, threshold) {
      //     // Return which of `color1` and `color2` has the greatest contrast with `color`
      //     // according to the standard WCAG contrast ratio calculation.
      //     // http://www.w3.org/TR/WCAG20/#contrast-ratiodef
      //     // The threshold param is no longer used, in line with SASS.
      //     // filter: contrast(3.2);
      //     // should be kept as is, so check for color
      //     if (!color.rgb) {
      //         return null;
      //     }
      //     if (typeof color1 === 'undefined') {
      //         color1 = colorFunctions.rgba(0, 0, 0, 1.0);
      //     }
      //     if (typeof color2 === 'undefined') {
      //         color2 = colorFunctions.rgba(255, 255, 255, 1.0);
      //     }
      //     var contrast1, contrast2;
      //     var luma = color.luma();
      //     var luma1 = color1.luma();
      //     var luma2 = color2.luma();
      //     // Calculate contrast ratios for each color
      //     if (luma > luma1) {
      //         contrast1 = (luma + 0.05) / (luma1 + 0.05);
      //     } else {
      //         contrast1 = (luma1 + 0.05) / (luma + 0.05);
      //     }
      //     if (luma > luma2) {
      //         contrast2 = (luma + 0.05) / (luma2 + 0.05);
      //     } else {
      //         contrast2 = (luma2 + 0.05) / (luma + 0.05);
      //     }
      //     if (contrast1 > contrast2) {
      //         return color1;
      //     } else {
      //         return color2;
      //     }
      // },
      argb: function argb(color) {
        return new Anonymous(color.toARGB());
      },
      color: function color(c) {
        if (c instanceof Quoted && /^#([A-Fa-f0-9]{8}|[A-Fa-f0-9]{6}|[A-Fa-f0-9]{3,4})$/i.test(c.value)) {
          var val = c.value.slice(1);
          return new Color(val, undefined, "#".concat(val));
        }
  
        if (c instanceof Color || (c = Color.fromKeyword(c.value))) {
          c.value = undefined;
          return c;
        }
  
        throw {
          type: 'Argument',
          message: 'argument must be a color keyword or 3|4|6|8 digit hex e.g. #FFF'
        };
      },
      tint: function tint(color, amount) {
        return colorFunctions.mix(colorFunctions.rgb(255, 255, 255), color, amount);
      },
      shade: function shade(color, amount) {
        return colorFunctions.mix(colorFunctions.rgb(0, 0, 0), color, amount);
      }
    };
    var color = colorFunctions;
  
    // ref: http://www.w3.org/TR/compositing-1
  
    function colorBlend(mode, color1, color2) {
      var ab = color1.alpha; // result
  
      var // backdrop
      cb;
      var as = color2.alpha;
      var // source
      cs;
      var ar;
      var cr;
      var r = [];
      ar = as + ab * (1 - as);
  
      for (var i = 0; i < 3; i++) {
        cb = color1.rgb[i] / 255;
        cs = color2.rgb[i] / 255;
        cr = mode(cb, cs);
  
        if (ar) {
          cr = (as * cs + ab * (cb - as * (cb + cs - cr))) / ar;
        }
  
        r[i] = cr * 255;
      }
  
      return new Color(r, ar);
    }
  
    var colorBlendModeFunctions = {
      multiply: function multiply(cb, cs) {
        return cb * cs;
      },
      screen: function screen(cb, cs) {
        return cb + cs - cb * cs;
      },
      overlay: function overlay(cb, cs) {
        cb *= 2;
        return cb <= 1 ? colorBlendModeFunctions.multiply(cb, cs) : colorBlendModeFunctions.screen(cb - 1, cs);
      },
      softlight: function softlight(cb, cs) {
        var d = 1;
        var e = cb;
  
        if (cs > 0.5) {
          e = 1;
          d = cb > 0.25 ? Math.sqrt(cb) : ((16 * cb - 12) * cb + 4) * cb;
        }
  
        return cb - (1 - 2 * cs) * e * (d - cb);
      },
      hardlight: function hardlight(cb, cs) {
        return colorBlendModeFunctions.overlay(cs, cb);
      },
      difference: function difference(cb, cs) {
        return Math.abs(cb - cs);
      },
      exclusion: function exclusion(cb, cs) {
        return cb + cs - 2 * cb * cs;
      },
      // non-w3c functions:
      average: function average(cb, cs) {
        return (cb + cs) / 2;
      },
      negation: function negation(cb, cs) {
        return 1 - Math.abs(cb + cs - 1);
      }
    };
  
    for (var f in colorBlendModeFunctions) {
      if (colorBlendModeFunctions.hasOwnProperty(f)) {
        colorBlend[f] = colorBlend.bind(null, colorBlendModeFunctions[f]);
      }
    }
  
    var dataUri = (function (environment) {
      var fallback = function fallback(functionThis, node) {
        return new URL(node, functionThis.index, functionThis.currentFileInfo).eval(functionThis.context);
      };
  
      return {
        'data-uri': function dataUri(mimetypeNode, filePathNode) {
          if (!filePathNode) {
            filePathNode = mimetypeNode;
            mimetypeNode = null;
          }
  
          var mimetype = mimetypeNode && mimetypeNode.value;
          var filePath = filePathNode.value;
          var currentFileInfo = this.currentFileInfo;
          var currentDirectory = currentFileInfo.rewriteUrls ? currentFileInfo.currentDirectory : currentFileInfo.entryPath;
          var fragmentStart = filePath.indexOf('#');
          var fragment = '';
  
          if (fragmentStart !== -1) {
            fragment = filePath.slice(fragmentStart);
            filePath = filePath.slice(0, fragmentStart);
          }
  
          var context = clone(this.context);
          context.rawBuffer = true;
          var fileManager = environment.getFileManager(filePath, currentDirectory, context, environment, true);
  
          if (!fileManager) {
            return fallback(this, filePathNode);
          }
  
          var useBase64 = false; // detect the mimetype if not given
  
          if (!mimetypeNode) {
            mimetype = environment.mimeLookup(filePath);
  
            if (mimetype === 'image/svg+xml') {
              useBase64 = false;
            } else {
              // use base 64 unless it's an ASCII or UTF-8 format
              var charset = environment.charsetLookup(mimetype);
              useBase64 = ['US-ASCII', 'UTF-8'].indexOf(charset) < 0;
            }
  
            if (useBase64) {
              mimetype += ';base64';
            }
          } else {
            useBase64 = /;base64$/.test(mimetype);
          }
  
          var fileSync = fileManager.loadFileSync(filePath, currentDirectory, context, environment);
  
          if (!fileSync.contents) {
            logger.warn("Skipped data-uri embedding of ".concat(filePath, " because file not found"));
            return fallback(this, filePathNode || mimetypeNode);
          }
  
          var buf = fileSync.contents;
  
          if (useBase64 && !environment.encodeBase64) {
            return fallback(this, filePathNode);
          }
  
          buf = useBase64 ? environment.encodeBase64(buf) : encodeURIComponent(buf);
          var uri = "data:".concat(mimetype, ",").concat(buf).concat(fragment);
          return new URL(new Quoted("\"".concat(uri, "\""), uri, false, this.index, this.currentFileInfo), this.index, this.currentFileInfo);
        }
      };
    });
  
    var getItemsFromNode = function getItemsFromNode(node) {
      // handle non-array values as an array of length 1
      // return 'undefined' if index is invalid
      var items = Array.isArray(node.value) ? node.value : Array(node);
      return items;
    };
  
    var list = {
      _SELF: function _SELF(n) {
        return n;
      },
      extract: function extract(values, index) {
        // (1-based index)
        index = index.value - 1;
        return getItemsFromNode(values)[index];
      },
      length: function length(values) {
        return new Dimension(getItemsFromNode(values).length);
      },
  
      /**
       * Creates a Less list of incremental values.
       * Modeled after Lodash's range function, also exists natively in PHP
       * 
       * @param {Dimension} [start=1]
       * @param {Dimension} end  - e.g. 10 or 10px - unit is added to output
       * @param {Dimension} [step=1] 
       */
      range: function range(start, end, step) {
        var from;
        var to;
        var stepValue = 1;
        var list = [];
  
        if (end) {
          to = end;
          from = start.value;
  
          if (step) {
            stepValue = step.value;
          }
        } else {
          from = 1;
          to = start;
        }
  
        for (var i = from; i <= to.value; i += stepValue) {
          list.push(new Dimension(i, to.unit));
        }
  
        return new Expression(list);
      },
      each: function each(list, rs) {
        var rules = [];
        var newRules;
        var iterator;
  
        if (list.value && !(list instanceof Quoted)) {
          if (Array.isArray(list.value)) {
            iterator = list.value;
          } else {
            iterator = [list.value];
          }
        } else if (list.ruleset) {
          iterator = list.ruleset.rules;
        } else if (list.rules) {
          iterator = list.rules;
        } else if (Array.isArray(list)) {
          iterator = list;
        } else {
          iterator = [list];
        }
  
        var valueName = '@value';
        var keyName = '@key';
        var indexName = '@index';
  
        if (rs.params) {
          valueName = rs.params[0] && rs.params[0].name;
          keyName = rs.params[1] && rs.params[1].name;
          indexName = rs.params[2] && rs.params[2].name;
          rs = rs.rules;
        } else {
          rs = rs.ruleset;
        }
  
        for (var i = 0; i < iterator.length; i++) {
          var key = void 0;
          var value = void 0;
          var item = iterator[i];
  
          if (item instanceof Declaration) {
            key = typeof item.name === 'string' ? item.name : item.name[0].value;
            value = item.value;
          } else {
            key = new Dimension(i + 1);
            value = item;
          }
  
          if (item instanceof Comment) {
            continue;
          }
  
          newRules = rs.rules.slice(0);
  
          if (valueName) {
            newRules.push(new Declaration(valueName, value, false, false, this.index, this.currentFileInfo));
          }
  
          if (indexName) {
            newRules.push(new Declaration(indexName, new Dimension(i + 1), false, false, this.index, this.currentFileInfo));
          }
  
          if (keyName) {
            newRules.push(new Declaration(keyName, key, false, false, this.index, this.currentFileInfo));
          }
  
          rules.push(new Ruleset([new Selector([new Element("", '&')])], newRules, rs.strictImports, rs.visibilityInfo()));
        }
  
        return new Ruleset([new Selector([new Element("", '&')])], rules, rs.strictImports, rs.visibilityInfo()).eval(this.context);
      }
    };
  
    var MathHelper = function MathHelper(fn, unit, n) {
      if (!(n instanceof Dimension)) {
        throw {
          type: 'Argument',
          message: 'argument must be a number'
        };
      }
  
      if (unit == null) {
        unit = n.unit;
      } else {
        n = n.unify();
      }
  
      return new Dimension(fn(parseFloat(n.value)), unit);
    };
  
    var mathFunctions = {
      // name,  unit
      ceil: null,
      floor: null,
      sqrt: null,
      abs: null,
      tan: '',
      sin: '',
      cos: '',
      atan: 'rad',
      asin: 'rad',
      acos: 'rad'
    };
  
    for (var f$1 in mathFunctions) {
      if (mathFunctions.hasOwnProperty(f$1)) {
        mathFunctions[f$1] = MathHelper.bind(null, Math[f$1], mathFunctions[f$1]);
      }
    }
  
    mathFunctions.round = function (n, f) {
      var fraction = typeof f === 'undefined' ? 0 : f.value;
      return MathHelper(function (num) {
        return num.toFixed(fraction);
      }, null, n);
    };
  
    var minMax = function minMax(isMin, args) {
      args = Array.prototype.slice.call(args);
  
      switch (args.length) {
        case 0:
          throw {
            type: 'Argument',
            message: 'one or more arguments required'
          };
      }
  
      var i; // key is the unit.toString() for unified Dimension values,
  
      var j;
      var current;
      var currentUnified;
      var referenceUnified;
      var unit;
      var unitStatic;
      var unitClone;
      var // elems only contains original argument values.
      order = [];
      var values = {}; // value is the index into the order array.
  
      for (i = 0; i < args.length; i++) {
        current = args[i];
  
        if (!(current instanceof Dimension)) {
          if (Array.isArray(args[i].value)) {
            Array.prototype.push.apply(args, Array.prototype.slice.call(args[i].value));
          }
  
          continue;
        }
  
        currentUnified = current.unit.toString() === '' && unitClone !== undefined ? new Dimension(current.value, unitClone).unify() : current.unify();
        unit = currentUnified.unit.toString() === '' && unitStatic !== undefined ? unitStatic : currentUnified.unit.toString();
        unitStatic = unit !== '' && unitStatic === undefined || unit !== '' && order[0].unify().unit.toString() === '' ? unit : unitStatic;
        unitClone = unit !== '' && unitClone === undefined ? current.unit.toString() : unitClone;
        j = values[''] !== undefined && unit !== '' && unit === unitStatic ? values[''] : values[unit];
  
        if (j === undefined) {
          if (unitStatic !== undefined && unit !== unitStatic) {
            throw {
              type: 'Argument',
              message: 'incompatible types'
            };
          }
  
          values[unit] = order.length;
          order.push(current);
          continue;
        }
  
        referenceUnified = order[j].unit.toString() === '' && unitClone !== undefined ? new Dimension(order[j].value, unitClone).unify() : order[j].unify();
  
        if (isMin && currentUnified.value < referenceUnified.value || !isMin && currentUnified.value > referenceUnified.value) {
          order[j] = current;
        }
      }
  
      if (order.length == 1) {
        return order[0];
      }
  
      args = order.map(function (a) {
        return a.toCSS(this.context);
      }).join(this.context.compress ? ',' : ', ');
      return new Anonymous("".concat(isMin ? 'min' : 'max', "(").concat(args, ")"));
    };
  
    var number$1 = {
      min: function min() {
        for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
          args[_key] = arguments[_key];
        }
  
        return minMax(true, args);
      },
      max: function max() {
        for (var _len2 = arguments.length, args = new Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
          args[_key2] = arguments[_key2];
        }
  
        return minMax(false, args);
      },
      convert: function convert(val, unit) {
        return val.convertTo(unit.value);
      },
      pi: function pi() {
        return new Dimension(Math.PI);
      },
      mod: function mod(a, b) {
        return new Dimension(a.value % b.value, a.unit);
      },
      pow: function pow(x, y) {
        if (typeof x === 'number' && typeof y === 'number') {
          x = new Dimension(x);
          y = new Dimension(y);
        } else if (!(x instanceof Dimension) || !(y instanceof Dimension)) {
          throw {
            type: 'Argument',
            message: 'arguments must be numbers'
          };
        }
  
        return new Dimension(Math.pow(x.value, y.value), x.unit);
      },
      percentage: function percentage(n) {
        var result = MathHelper(function (num) {
          return num * 100;
        }, '%', n);
        return result;
      }
    };
  
    var string = {
      e: function e(str) {
        return new Quoted('"', str instanceof JavaScript ? str.evaluated : str.value, true);
      },
      escape: function escape(str) {
        return new Anonymous(encodeURI(str.value).replace(/=/g, '%3D').replace(/:/g, '%3A').replace(/#/g, '%23').replace(/;/g, '%3B').replace(/\(/g, '%28').replace(/\)/g, '%29'));
      },
      replace: function replace(string, pattern, replacement, flags) {
        var result = string.value;
        replacement = replacement.type === 'Quoted' ? replacement.value : replacement.toCSS();
        result = result.replace(new RegExp(pattern.value, flags ? flags.value : ''), replacement);
        return new Quoted(string.quote || '', result, string.escaped);
      },
      '%': function _(string
      /* arg, arg, ... */
      ) {
        var args = Array.prototype.slice.call(arguments, 1);
        var result = string.value;
  
        var _loop = function _loop(i) {
          /* jshint loopfunc:true */
          result = result.replace(/%[sda]/i, function (token) {
            var value = args[i].type === 'Quoted' && token.match(/s/i) ? args[i].value : args[i].toCSS();
            return token.match(/[A-Z]$/) ? encodeURIComponent(value) : value;
          });
        };
  
        for (var i = 0; i < args.length; i++) {
          _loop(i);
        }
  
        result = result.replace(/%%/g, '%');
        return new Quoted(string.quote || '', result, string.escaped);
      }
    };
  
    var svg = (function (environment) {
      return {
        'svg-gradient': function svgGradient(direction) {
          var stops;
          var gradientDirectionSvg;
          var gradientType = 'linear';
          var rectangleDimension = 'x="0" y="0" width="1" height="1"';
          var renderEnv = {
            compress: false
          };
          var returner;
          var directionValue = direction.toCSS(renderEnv);
          var i;
          var color;
          var position;
          var positionValue;
          var alpha;
  
          function throwArgumentDescriptor() {
            throw {
              type: 'Argument',
              message: 'svg-gradient expects direction, start_color [start_position], [color position,]...,' + ' end_color [end_position] or direction, color list'
            };
          }
  
          if (arguments.length == 2) {
            if (arguments[1].value.length < 2) {
              throwArgumentDescriptor();
            }
  
            stops = arguments[1].value;
          } else if (arguments.length < 3) {
            throwArgumentDescriptor();
          } else {
            stops = Array.prototype.slice.call(arguments, 1);
          }
  
          switch (directionValue) {
            case 'to bottom':
              gradientDirectionSvg = 'x1="0%" y1="0%" x2="0%" y2="100%"';
              break;
  
            case 'to right':
              gradientDirectionSvg = 'x1="0%" y1="0%" x2="100%" y2="0%"';
              break;
  
            case 'to bottom right':
              gradientDirectionSvg = 'x1="0%" y1="0%" x2="100%" y2="100%"';
              break;
  
            case 'to top right':
              gradientDirectionSvg = 'x1="0%" y1="100%" x2="100%" y2="0%"';
              break;
  
            case 'ellipse':
            case 'ellipse at center':
              gradientType = 'radial';
              gradientDirectionSvg = 'cx="50%" cy="50%" r="75%"';
              rectangleDimension = 'x="-50" y="-50" width="101" height="101"';
              break;
  
            default:
              throw {
                type: 'Argument',
                message: 'svg-gradient direction must be \'to bottom\', \'to right\',' + ' \'to bottom right\', \'to top right\' or \'ellipse at center\''
              };
          }
  
          returner = "<svg xmlns=\"http://www.w3.org/2000/svg\" viewBox=\"0 0 1 1\"><".concat(gradientType, "Gradient id=\"g\" ").concat(gradientDirectionSvg, ">");
  
          for (i = 0; i < stops.length; i += 1) {
            if (stops[i] instanceof Expression) {
              color = stops[i].value[0];
              position = stops[i].value[1];
            } else {
              color = stops[i];
              position = undefined;
            }
  
            if (!(color instanceof Color) || !((i === 0 || i + 1 === stops.length) && position === undefined) && !(position instanceof Dimension)) {
              throwArgumentDescriptor();
            }
  
            positionValue = position ? position.toCSS(renderEnv) : i === 0 ? '0%' : '100%';
            alpha = color.alpha;
            returner += "<stop offset=\"".concat(positionValue, "\" stop-color=\"").concat(color.toRGB(), "\"").concat(alpha < 1 ? " stop-opacity=\"".concat(alpha, "\"") : '', "/>");
          }
  
          returner += "</".concat(gradientType, "Gradient><rect ").concat(rectangleDimension, " fill=\"url(#g)\" /></svg>");
          returner = encodeURIComponent(returner);
          returner = "data:image/svg+xml,".concat(returner);
          return new URL(new Quoted("'".concat(returner, "'"), returner, false, this.index, this.currentFileInfo), this.index, this.currentFileInfo);
        }
      };
    });
  
    var isa = function isa(n, Type) {
      return n instanceof Type ? Keyword.True : Keyword.False;
    };
  
    var isunit = function isunit(n, unit) {
      if (unit === undefined) {
        throw {
          type: 'Argument',
          message: 'missing the required second argument to isunit.'
        };
      }
  
      unit = typeof unit.value === 'string' ? unit.value : unit;
  
      if (typeof unit !== 'string') {
        throw {
          type: 'Argument',
          message: 'Second argument to isunit should be a unit or a string.'
        };
      }
  
      return n instanceof Dimension && n.unit.is(unit) ? Keyword.True : Keyword.False;
    };
  
    var types = {
      isruleset: function isruleset(n) {
        return isa(n, DetachedRuleset);
      },
      iscolor: function iscolor(n) {
        return isa(n, Color);
      },
      isnumber: function isnumber(n) {
        return isa(n, Dimension);
      },
      isstring: function isstring(n) {
        return isa(n, Quoted);
      },
      iskeyword: function iskeyword(n) {
        return isa(n, Keyword);
      },
      isurl: function isurl(n) {
        return isa(n, URL);
      },
      ispixel: function ispixel(n) {
        return isunit(n, 'px');
      },
      ispercentage: function ispercentage(n) {
        return isunit(n, '%');
      },
      isem: function isem(n) {
        return isunit(n, 'em');
      },
      isunit: isunit,
      unit: function unit(val, _unit) {
        if (!(val instanceof Dimension)) {
          throw {
            type: 'Argument',
            message: "the first argument to unit must be a number".concat(val instanceof Operation ? '. Have you forgotten parenthesis?' : '')
          };
        }
  
        if (_unit) {
          if (_unit instanceof Keyword) {
            _unit = _unit.value;
          } else {
            _unit = _unit.toCSS();
          }
        } else {
          _unit = '';
        }
  
        return new Dimension(val.value, _unit);
      },
      'get-unit': function getUnit(n) {
        return new Anonymous(n.unit);
      }
    };
  
    var Functions = (function (environment) {
      var functions = {
        functionRegistry: functionRegistry,
        functionCaller: functionCaller
      }; // register functions
  
      functionRegistry.addMultiple(boolean$1);
      functionRegistry.add('default', defaultFunc.eval.bind(defaultFunc));
      functionRegistry.addMultiple(color);
      functionRegistry.addMultiple(colorBlend);
      functionRegistry.addMultiple(dataUri(environment));
      functionRegistry.addMultiple(list);
      functionRegistry.addMultiple(mathFunctions);
      functionRegistry.addMultiple(number$1);
      functionRegistry.addMultiple(string);
      functionRegistry.addMultiple(svg());
      functionRegistry.addMultiple(types);
      return functions;
    });
  
    var sourceMapOutput = (function (environment) {
      var SourceMapOutput =
      /*#__PURE__*/
      function () {
        function SourceMapOutput(options) {
          _classCallCheck(this, SourceMapOutput);
  
          this._css = [];
          this._rootNode = options.rootNode;
          this._contentsMap = options.contentsMap;
          this._contentsIgnoredCharsMap = options.contentsIgnoredCharsMap;
  
          if (options.sourceMapFilename) {
            this._sourceMapFilename = options.sourceMapFilename.replace(/\\/g, '/');
          }
  
          this._outputFilename = options.outputFilename;
          this.sourceMapURL = options.sourceMapURL;
  
          if (options.sourceMapBasepath) {
            this._sourceMapBasepath = options.sourceMapBasepath.replace(/\\/g, '/');
          }
  
          if (options.sourceMapRootpath) {
            this._sourceMapRootpath = options.sourceMapRootpath.replace(/\\/g, '/');
  
            if (this._sourceMapRootpath.charAt(this._sourceMapRootpath.length - 1) !== '/') {
              this._sourceMapRootpath += '/';
            }
          } else {
            this._sourceMapRootpath = '';
          }
  
          this._outputSourceFiles = options.outputSourceFiles;
          this._sourceMapGeneratorConstructor = environment.getSourceMapGenerator();
          this._lineNumber = 0;
          this._column = 0;
        }
  
        _createClass(SourceMapOutput, [{
          key: "removeBasepath",
          value: function removeBasepath(path) {
            if (this._sourceMapBasepath && path.indexOf(this._sourceMapBasepath) === 0) {
              path = path.substring(this._sourceMapBasepath.length);
  
              if (path.charAt(0) === '\\' || path.charAt(0) === '/') {
                path = path.substring(1);
              }
            }
  
            return path;
          }
        }, {
          key: "normalizeFilename",
          value: function normalizeFilename(filename) {
            filename = filename.replace(/\\/g, '/');
            filename = this.removeBasepath(filename);
            return (this._sourceMapRootpath || '') + filename;
          }
        }, {
          key: "add",
          value: function add(chunk, fileInfo, index, mapLines) {
            // ignore adding empty strings
            if (!chunk) {
              return;
            }
  
            var lines;
            var sourceLines;
            var columns;
            var sourceColumns;
            var i;
  
            if (fileInfo && fileInfo.filename) {
              var inputSource = this._contentsMap[fileInfo.filename]; // remove vars/banner added to the top of the file
  
              if (this._contentsIgnoredCharsMap[fileInfo.filename]) {
                // adjust the index
                index -= this._contentsIgnoredCharsMap[fileInfo.filename];
  
                if (index < 0) {
                  index = 0;
                } // adjust the source
  
  
                inputSource = inputSource.slice(this._contentsIgnoredCharsMap[fileInfo.filename]);
              } // ignore empty content
  
  
              if (inputSource === undefined) {
                return;
              }
  
              inputSource = inputSource.substring(0, index);
              sourceLines = inputSource.split('\n');
              sourceColumns = sourceLines[sourceLines.length - 1];
            }
  
            lines = chunk.split('\n');
            columns = lines[lines.length - 1];
  
            if (fileInfo && fileInfo.filename) {
              if (!mapLines) {
                this._sourceMapGenerator.addMapping({
                  generated: {
                    line: this._lineNumber + 1,
                    column: this._column
                  },
                  original: {
                    line: sourceLines.length,
                    column: sourceColumns.length
                  },
                  source: this.normalizeFilename(fileInfo.filename)
                });
              } else {
                for (i = 0; i < lines.length; i++) {
                  this._sourceMapGenerator.addMapping({
                    generated: {
                      line: this._lineNumber + i + 1,
                      column: i === 0 ? this._column : 0
                    },
                    original: {
                      line: sourceLines.length + i,
                      column: i === 0 ? sourceColumns.length : 0
                    },
                    source: this.normalizeFilename(fileInfo.filename)
                  });
                }
              }
            }
  
            if (lines.length === 1) {
              this._column += columns.length;
            } else {
              this._lineNumber += lines.length - 1;
              this._column = columns.length;
            }
  
            this._css.push(chunk);
          }
        }, {
          key: "isEmpty",
          value: function isEmpty() {
            return this._css.length === 0;
          }
        }, {
          key: "toCSS",
          value: function toCSS(context) {
            this._sourceMapGenerator = new this._sourceMapGeneratorConstructor({
              file: this._outputFilename,
              sourceRoot: null
            });
  
            if (this._outputSourceFiles) {
              for (var filename in this._contentsMap) {
                if (this._contentsMap.hasOwnProperty(filename)) {
                  var source = this._contentsMap[filename];
  
                  if (this._contentsIgnoredCharsMap[filename]) {
                    source = source.slice(this._contentsIgnoredCharsMap[filename]);
                  }
  
                  this._sourceMapGenerator.setSourceContent(this.normalizeFilename(filename), source);
                }
              }
            }
  
            this._rootNode.genCSS(context, this);
  
            if (this._css.length > 0) {
              var sourceMapURL;
              var sourceMapContent = JSON.stringify(this._sourceMapGenerator.toJSON());
  
              if (this.sourceMapURL) {
                sourceMapURL = this.sourceMapURL;
              } else if (this._sourceMapFilename) {
                sourceMapURL = this._sourceMapFilename;
              }
  
              this.sourceMapURL = sourceMapURL;
              this.sourceMap = sourceMapContent;
            }
  
            return this._css.join('');
          }
        }]);
  
        return SourceMapOutput;
      }();
  
      return SourceMapOutput;
    });
  
    var sourceMapBuilder = (function (SourceMapOutput, environment) {
      var SourceMapBuilder =
      /*#__PURE__*/
      function () {
        function SourceMapBuilder(options) {
          _classCallCheck(this, SourceMapBuilder);
  
          this.options = options;
        }
  
        _createClass(SourceMapBuilder, [{
          key: "toCSS",
          value: function toCSS(rootNode, options, imports) {
            var sourceMapOutput = new SourceMapOutput({
              contentsIgnoredCharsMap: imports.contentsIgnoredChars,
              rootNode: rootNode,
              contentsMap: imports.contents,
              sourceMapFilename: this.options.sourceMapFilename,
              sourceMapURL: this.options.sourceMapURL,
              outputFilename: this.options.sourceMapOutputFilename,
              sourceMapBasepath: this.options.sourceMapBasepath,
              sourceMapRootpath: this.options.sourceMapRootpath,
              outputSourceFiles: this.options.outputSourceFiles,
              sourceMapGenerator: this.options.sourceMapGenerator,
              sourceMapFileInline: this.options.sourceMapFileInline
            });
            var css = sourceMapOutput.toCSS(options);
            this.sourceMap = sourceMapOutput.sourceMap;
            this.sourceMapURL = sourceMapOutput.sourceMapURL;
  
            if (this.options.sourceMapInputFilename) {
              this.sourceMapInputFilename = sourceMapOutput.normalizeFilename(this.options.sourceMapInputFilename);
            }
  
            if (this.options.sourceMapBasepath !== undefined && this.sourceMapURL !== undefined) {
              this.sourceMapURL = sourceMapOutput.removeBasepath(this.sourceMapURL);
            }
  
            return css + this.getCSSAppendage();
          }
        }, {
          key: "getCSSAppendage",
          value: function getCSSAppendage() {
            var sourceMapURL = this.sourceMapURL;
  
            if (this.options.sourceMapFileInline) {
              if (this.sourceMap === undefined) {
                return '';
              }
  
              sourceMapURL = "data:application/json;base64,".concat(environment.encodeBase64(this.sourceMap));
            }
  
            if (sourceMapURL) {
              return "/*# sourceMappingURL=".concat(sourceMapURL, " */");
            }
  
            return '';
          }
        }, {
          key: "getExternalSourceMap",
          value: function getExternalSourceMap() {
            return this.sourceMap;
          }
        }, {
          key: "setExternalSourceMap",
          value: function setExternalSourceMap(sourceMap) {
            this.sourceMap = sourceMap;
          }
        }, {
          key: "isInline",
          value: function isInline() {
            return this.options.sourceMapFileInline;
          }
        }, {
          key: "getSourceMapURL",
          value: function getSourceMapURL() {
            return this.sourceMapURL;
          }
        }, {
          key: "getOutputFilename",
          value: function getOutputFilename() {
            return this.options.sourceMapOutputFilename;
          }
        }, {
          key: "getInputFilename",
          value: function getInputFilename() {
            return this.sourceMapInputFilename;
          }
        }]);
  
        return SourceMapBuilder;
      }();
  
      return SourceMapBuilder;
    });
  
    var transformTree = (function (root) {
      var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
      var evaldRoot;
      var variables = options.variables;
      var evalEnv = new contexts.Eval(options); //
      // Allows setting variables with a hash, so:
      //
      //   `{ color: new tree.Color('#f01') }` will become:
      //
      //   new tree.Declaration('@color',
      //     new tree.Value([
      //       new tree.Expression([
      //         new tree.Color('#f01')
      //       ])
      //     ])
      //   )
      //
  
      if (_typeof(variables) === 'object' && !Array.isArray(variables)) {
        variables = Object.keys(variables).map(function (k) {
          var value = variables[k];
  
          if (!(value instanceof tree.Value)) {
            if (!(value instanceof tree.Expression)) {
              value = new tree.Expression([value]);
            }
  
            value = new tree.Value([value]);
          }
  
          return new tree.Declaration("@".concat(k), value, false, null, 0);
        });
        evalEnv.frames = [new tree.Ruleset(null, variables)];
      }
  
      var visitors$1 = [new visitors.JoinSelectorVisitor(), new visitors.MarkVisibleSelectorsVisitor(true), new visitors.ExtendVisitor(), new visitors.ToCSSVisitor({
        compress: Boolean(options.compress)
      })];
      var preEvalVisitors = [];
      var v;
      var visitorIterator;
      /**
       * first() / get() allows visitors to be added while visiting
       * 
       * @todo Add scoping for visitors just like functions for @plugin; right now they're global
       */
  
      if (options.pluginManager) {
        visitorIterator = options.pluginManager.visitor();
  
        for (var i = 0; i < 2; i++) {
          visitorIterator.first();
  
          while (v = visitorIterator.get()) {
            if (v.isPreEvalVisitor) {
              if (i === 0 || preEvalVisitors.indexOf(v) === -1) {
                preEvalVisitors.push(v);
                v.run(root);
              }
            } else {
              if (i === 0 || visitors$1.indexOf(v) === -1) {
                if (v.isPreVisitor) {
                  visitors$1.unshift(v);
                } else {
                  visitors$1.push(v);
                }
              }
            }
          }
        }
      }
  
      evaldRoot = root.eval(evalEnv);
  
      for (var i = 0; i < visitors$1.length; i++) {
        visitors$1[i].run(evaldRoot);
      } // Run any remaining visitors added after eval pass
  
  
      if (options.pluginManager) {
        visitorIterator.first();
  
        while (v = visitorIterator.get()) {
          if (visitors$1.indexOf(v) === -1 && preEvalVisitors.indexOf(v) === -1) {
            v.run(evaldRoot);
          }
        }
      }
  
      return evaldRoot;
    });
  
    var parseTree = (function (SourceMapBuilder) {
      var ParseTree =
      /*#__PURE__*/
      function () {
        function ParseTree(root, imports) {
          _classCallCheck(this, ParseTree);
  
          this.root = root;
          this.imports = imports;
        }
  
        _createClass(ParseTree, [{
          key: "toCSS",
          value: function toCSS(options) {
            var evaldRoot;
            var result = {};
            var sourceMapBuilder;
  
            try {
              evaldRoot = transformTree(this.root, options);
            } catch (e) {
              throw new LessError(e, this.imports);
            }
  
            try {
              var compress = Boolean(options.compress);
  
              if (compress) {
                logger.warn('The compress option has been deprecated. ' + 'We recommend you use a dedicated css minifier, for instance see less-plugin-clean-css.');
              }
  
              var toCSSOptions = {
                compress: compress,
                dumpLineNumbers: options.dumpLineNumbers,
                strictUnits: Boolean(options.strictUnits),
                numPrecision: 8
              };
  
              if (options.sourceMap) {
                sourceMapBuilder = new SourceMapBuilder(options.sourceMap);
                result.css = sourceMapBuilder.toCSS(evaldRoot, toCSSOptions, this.imports);
              } else {
                result.css = evaldRoot.toCSS(toCSSOptions);
              }
            } catch (e) {
              throw new LessError(e, this.imports);
            }
  
            if (options.pluginManager) {
              var postProcessors = options.pluginManager.getPostProcessors();
  
              for (var i = 0; i < postProcessors.length; i++) {
                result.css = postProcessors[i].process(result.css, {
                  sourceMap: sourceMapBuilder,
                  options: options,
                  imports: this.imports
                });
              }
            }
  
            if (options.sourceMap) {
              result.map = sourceMapBuilder.getExternalSourceMap();
            }
  
            result.imports = [];
  
            for (var file in this.imports.files) {
              if (this.imports.files.hasOwnProperty(file) && file !== this.imports.rootFilename) {
                result.imports.push(file);
              }
            }
  
            return result;
          }
        }]);
  
        return ParseTree;
      }();
  
      return ParseTree;
    });
  
    var importManager = (function (environment) {
      // FileInfo = {
      //  'rewriteUrls' - option - whether to adjust URL's to be relative
      //  'filename' - full resolved filename of current file
      //  'rootpath' - path to append to normal URLs for this node
      //  'currentDirectory' - path to the current file, absolute
      //  'rootFilename' - filename of the base file
      //  'entryPath' - absolute path to the entry file
      //  'reference' - whether the file should not be output and only output parts that are referenced
      var ImportManager =
      /*#__PURE__*/
      function () {
        function ImportManager(less, context, rootFileInfo) {
          _classCallCheck(this, ImportManager);
  
          this.less = less;
          this.rootFilename = rootFileInfo.filename;
          this.paths = context.paths || []; // Search paths, when importing
  
          this.contents = {}; // map - filename to contents of all the files
  
          this.contentsIgnoredChars = {}; // map - filename to lines at the beginning of each file to ignore
  
          this.mime = context.mime;
          this.error = null;
          this.context = context; // Deprecated? Unused outside of here, could be useful.
  
          this.queue = []; // Files which haven't been imported yet
  
          this.files = {}; // Holds the imported parse trees.
        }
        /**
         * Add an import to be imported
         * @param path - the raw path
         * @param tryAppendExtension - whether to try appending a file extension (.less or .js if the path has no extension)
         * @param currentFileInfo - the current file info (used for instance to work out relative paths)
         * @param importOptions - import options
         * @param callback - callback for when it is imported
         */
  
  
        _createClass(ImportManager, [{
          key: "push",
          value: function push(path, tryAppendExtension, currentFileInfo, importOptions, callback) {
            var importManager = this;
            var pluginLoader = this.context.pluginManager.Loader;
            this.queue.push(path);
  
            var fileParsedFunc = function fileParsedFunc(e, root, fullPath) {
              importManager.queue.splice(importManager.queue.indexOf(path), 1); // Remove the path from the queue
  
              var importedEqualsRoot = fullPath === importManager.rootFilename;
  
              if (importOptions.optional && e) {
                callback(null, {
                  rules: []
                }, false, null);
                logger.info("The file ".concat(fullPath, " was skipped because it was not found and the import was marked optional."));
              } else {
                // Inline imports aren't cached here.
                // If we start to cache them, please make sure they won't conflict with non-inline imports of the
                // same name as they used to do before this comment and the condition below have been added.
                if (!importManager.files[fullPath] && !importOptions.inline) {
                  importManager.files[fullPath] = {
                    root: root,
                    options: importOptions
                  };
                }
  
                if (e && !importManager.error) {
                  importManager.error = e;
                }
  
                callback(e, root, importedEqualsRoot, fullPath);
              }
            };
  
            var newFileInfo = {
              rewriteUrls: this.context.rewriteUrls,
              entryPath: currentFileInfo.entryPath,
              rootpath: currentFileInfo.rootpath,
              rootFilename: currentFileInfo.rootFilename
            };
            var fileManager = environment.getFileManager(path, currentFileInfo.currentDirectory, this.context, environment);
  
            if (!fileManager) {
              fileParsedFunc({
                message: "Could not find a file-manager for ".concat(path)
              });
              return;
            }
  
            var loadFileCallback = function loadFileCallback(loadedFile) {
              var plugin;
              var resolvedFilename = loadedFile.filename;
              var contents = loadedFile.contents.replace(/^\uFEFF/, ''); // Pass on an updated rootpath if path of imported file is relative and file
              // is in a (sub|sup) directory
              //
              // Examples:
              // - If path of imported file is 'module/nav/nav.less' and rootpath is 'less/',
              //   then rootpath should become 'less/module/nav/'
              // - If path of imported file is '../mixins.less' and rootpath is 'less/',
              //   then rootpath should become 'less/../'
  
              newFileInfo.currentDirectory = fileManager.getPath(resolvedFilename);
  
              if (newFileInfo.rewriteUrls) {
                newFileInfo.rootpath = fileManager.join(importManager.context.rootpath || '', fileManager.pathDiff(newFileInfo.currentDirectory, newFileInfo.entryPath));
  
                if (!fileManager.isPathAbsolute(newFileInfo.rootpath) && fileManager.alwaysMakePathsAbsolute()) {
                  newFileInfo.rootpath = fileManager.join(newFileInfo.entryPath, newFileInfo.rootpath);
                }
              }
  
              newFileInfo.filename = resolvedFilename;
              var newEnv = new contexts.Parse(importManager.context);
              newEnv.processImports = false;
              importManager.contents[resolvedFilename] = contents;
  
              if (currentFileInfo.reference || importOptions.reference) {
                newFileInfo.reference = true;
              }
  
              if (importOptions.isPlugin) {
                plugin = pluginLoader.evalPlugin(contents, newEnv, importManager, importOptions.pluginArgs, newFileInfo);
  
                if (plugin instanceof LessError) {
                  fileParsedFunc(plugin, null, resolvedFilename);
                } else {
                  fileParsedFunc(null, plugin, resolvedFilename);
                }
              } else if (importOptions.inline) {
                fileParsedFunc(null, contents, resolvedFilename);
              } else {
                // import (multiple) parse trees apparently get altered and can't be cached.
                // TODO: investigate why this is
                if (importManager.files[resolvedFilename] && !importManager.files[resolvedFilename].options.multiple && !importOptions.multiple) {
                  fileParsedFunc(null, importManager.files[resolvedFilename].root, resolvedFilename);
                } else {
                  new Parser(newEnv, importManager, newFileInfo).parse(contents, function (e, root) {
                    fileParsedFunc(e, root, resolvedFilename);
                  });
                }
              }
            };
  
            var promise;
            var context = clone(this.context);
  
            if (tryAppendExtension) {
              context.ext = importOptions.isPlugin ? '.js' : '.less';
            }
  
            if (importOptions.isPlugin) {
              context.mime = 'application/javascript';
              promise = pluginLoader.loadPlugin(path, currentFileInfo.currentDirectory, context, environment, fileManager);
            } else {
              promise = fileManager.loadFile(path, currentFileInfo.currentDirectory, context, environment, function (err, loadedFile) {
                if (err) {
                  fileParsedFunc(err);
                } else {
                  loadFileCallback(loadedFile);
                }
              });
            }
  
            if (promise) {
              promise.then(loadFileCallback, fileParsedFunc);
            }
          }
        }]);
  
        return ImportManager;
      }();
  
      return ImportManager;
    });
  
    var Render = (function (environment, ParseTree, ImportManager) {
      var render = function render(input, options, callback) {
        if (typeof options === 'function') {
          callback = options;
          options = copyOptions(this.options, {});
        } else {
          options = copyOptions(this.options, options || {});
        }
  
        if (!callback) {
          var self = this;
          return new Promise(function (resolve, reject) {
            render.call(self, input, options, function (err, output) {
              if (err) {
                reject(err);
              } else {
                resolve(output);
              }
            });
          });
        } else {
          this.parse(input, options, function (err, root, imports, options) {
            if (err) {
              return callback(err);
            }
  
            var result;
  
            try {
              var parseTree = new ParseTree(root, imports);
              result = parseTree.toCSS(options);
            } catch (err) {
              return callback(err);
            }
  
            callback(null, result);
          });
        }
      };
  
      return render;
    });
  
    /**
     * Plugin Manager
     */
    var PluginManager =
    /*#__PURE__*/
    function () {
      function PluginManager(less) {
        _classCallCheck(this, PluginManager);
  
        this.less = less;
        this.visitors = [];
        this.preProcessors = [];
        this.postProcessors = [];
        this.installedPlugins = [];
        this.fileManagers = [];
        this.iterator = -1;
        this.pluginCache = {};
        this.Loader = new less.PluginLoader(less);
      }
      /**
       * Adds all the plugins in the array
       * @param {Array} plugins
       */
  
  
      _createClass(PluginManager, [{
        key: "addPlugins",
        value: function addPlugins(plugins) {
          if (plugins) {
            for (var i = 0; i < plugins.length; i++) {
              this.addPlugin(plugins[i]);
            }
          }
        }
        /**
         *
         * @param plugin
         * @param {String} filename
         */
  
      }, {
        key: "addPlugin",
        value: function addPlugin(plugin, filename, functionRegistry) {
          this.installedPlugins.push(plugin);
  
          if (filename) {
            this.pluginCache[filename] = plugin;
          }
  
          if (plugin.install) {
            plugin.install(this.less, this, functionRegistry || this.less.functions.functionRegistry);
          }
        }
        /**
         *
         * @param filename
         */
  
      }, {
        key: "get",
        value: function get(filename) {
          return this.pluginCache[filename];
        }
        /**
         * Adds a visitor. The visitor object has options on itself to determine
         * when it should run.
         * @param visitor
         */
  
      }, {
        key: "addVisitor",
        value: function addVisitor(visitor) {
          this.visitors.push(visitor);
        }
        /**
         * Adds a pre processor object
         * @param {object} preProcessor
         * @param {number} priority - guidelines 1 = before import, 1000 = import, 2000 = after import
         */
  
      }, {
        key: "addPreProcessor",
        value: function addPreProcessor(preProcessor, priority) {
          var indexToInsertAt;
  
          for (indexToInsertAt = 0; indexToInsertAt < this.preProcessors.length; indexToInsertAt++) {
            if (this.preProcessors[indexToInsertAt].priority >= priority) {
              break;
            }
          }
  
          this.preProcessors.splice(indexToInsertAt, 0, {
            preProcessor: preProcessor,
            priority: priority
          });
        }
        /**
         * Adds a post processor object
         * @param {object} postProcessor
         * @param {number} priority - guidelines 1 = before compression, 1000 = compression, 2000 = after compression
         */
  
      }, {
        key: "addPostProcessor",
        value: function addPostProcessor(postProcessor, priority) {
          var indexToInsertAt;
  
          for (indexToInsertAt = 0; indexToInsertAt < this.postProcessors.length; indexToInsertAt++) {
            if (this.postProcessors[indexToInsertAt].priority >= priority) {
              break;
            }
          }
  
          this.postProcessors.splice(indexToInsertAt, 0, {
            postProcessor: postProcessor,
            priority: priority
          });
        }
        /**
         *
         * @param manager
         */
  
      }, {
        key: "addFileManager",
        value: function addFileManager(manager) {
          this.fileManagers.push(manager);
        }
        /**
         *
         * @returns {Array}
         * @private
         */
  
      }, {
        key: "getPreProcessors",
        value: function getPreProcessors() {
          var preProcessors = [];
  
          for (var i = 0; i < this.preProcessors.length; i++) {
            preProcessors.push(this.preProcessors[i].preProcessor);
          }
  
          return preProcessors;
        }
        /**
         *
         * @returns {Array}
         * @private
         */
  
      }, {
        key: "getPostProcessors",
        value: function getPostProcessors() {
          var postProcessors = [];
  
          for (var i = 0; i < this.postProcessors.length; i++) {
            postProcessors.push(this.postProcessors[i].postProcessor);
          }
  
          return postProcessors;
        }
        /**
         *
         * @returns {Array}
         * @private
         */
  
      }, {
        key: "getVisitors",
        value: function getVisitors() {
          return this.visitors;
        }
      }, {
        key: "visitor",
        value: function visitor() {
          var self = this;
          return {
            first: function first() {
              self.iterator = -1;
              return self.visitors[self.iterator];
            },
            get: function get() {
              self.iterator += 1;
              return self.visitors[self.iterator];
            }
          };
        }
        /**
         *
         * @returns {Array}
         * @private
         */
  
      }, {
        key: "getFileManagers",
        value: function getFileManagers() {
          return this.fileManagers;
        }
      }]);
  
      return PluginManager;
    }();
  
    var pm;
  
    function PluginManagerFactory(less, newFactory) {
      if (newFactory || !pm) {
        pm = new PluginManager(less);
      }
  
      return pm;
    }
  
    var Parse = (function (environment, ParseTree, ImportManager) {
      var parse = function parse(input, options, callback) {
        if (typeof options === 'function') {
          callback = options;
          options = copyOptions(this.options, {});
        } else {
          options = copyOptions(this.options, options || {});
        }
  
        if (!callback) {
          var self = this;
          return new Promise(function (resolve, reject) {
            parse.call(self, input, options, function (err, output) {
              if (err) {
                reject(err);
              } else {
                resolve(output);
              }
            });
          });
        } else {
          var context;
          var rootFileInfo;
          var pluginManager = new PluginManagerFactory(this, !options.reUsePluginManager);
          options.pluginManager = pluginManager;
          context = new contexts.Parse(options);
  
          if (options.rootFileInfo) {
            rootFileInfo = options.rootFileInfo;
          } else {
            var filename = options.filename || 'input';
            var entryPath = filename.replace(/[^\/\\]*$/, '');
            rootFileInfo = {
              filename: filename,
              rewriteUrls: context.rewriteUrls,
              rootpath: context.rootpath || '',
              currentDirectory: entryPath,
              entryPath: entryPath,
              rootFilename: filename
            }; // add in a missing trailing slash
  
            if (rootFileInfo.rootpath && rootFileInfo.rootpath.slice(-1) !== '/') {
              rootFileInfo.rootpath += '/';
            }
          }
  
          var imports = new ImportManager(this, context, rootFileInfo);
          this.importManager = imports; // TODO: allow the plugins to be just a list of paths or names
          // Do an async plugin queue like lessc
  
          if (options.plugins) {
            options.plugins.forEach(function (plugin) {
              var evalResult;
              var contents;
  
              if (plugin.fileContent) {
                contents = plugin.fileContent.replace(/^\uFEFF/, '');
                evalResult = pluginManager.Loader.evalPlugin(contents, context, imports, plugin.options, plugin.filename);
  
                if (evalResult instanceof LessError) {
                  return callback(evalResult);
                }
              } else {
                pluginManager.addPlugin(plugin);
              }
            });
          }
  
          new Parser(context, imports, rootFileInfo).parse(input, function (e, root) {
            if (e) {
              return callback(e);
            }
  
            callback(null, root, imports, options);
          }, options);
        }
      };
  
      return parse;
    });
  
    var lessRoot = (function (environment$1, fileManagers) {
      /**
       * @todo
       * This original code could be improved quite a bit.
       * Many classes / modules currently add side-effects / mutations to passed in objects,
       * which makes it hard to refactor and reason about. 
       */
      environment$1 = new environment(environment$1, fileManagers);
      var SourceMapOutput = sourceMapOutput(environment$1);
      var SourceMapBuilder = sourceMapBuilder(SourceMapOutput, environment$1);
      var ParseTree = parseTree(SourceMapBuilder);
      var ImportManager = importManager(environment$1);
      var render = Render(environment$1, ParseTree);
      var parse = Parse(environment$1, ParseTree, ImportManager);
      var functions = Functions(environment$1);
      /**
       * @todo
       * This root properties / methods need to be organized.
       * It's not clear what should / must be public and why.
       */
  
      var initial = {
        version: [3, 10, 3],
        data: data,
        tree: tree,
        Environment: environment,
        AbstractFileManager: AbstractFileManager,
        AbstractPluginLoader: AbstractPluginLoader,
        environment: environment$1,
        visitors: visitors,
        Parser: Parser,
        functions: functions,
        contexts: contexts,
        SourceMapOutput: SourceMapOutput,
        SourceMapBuilder: SourceMapBuilder,
        ParseTree: ParseTree,
        ImportManager: ImportManager,
        render: render,
        parse: parse,
        LessError: LessError,
        transformTree: transformTree,
        utils: utils,
        PluginManager: PluginManagerFactory,
        logger: logger
      }; // Create a public API
  
      var ctor = function ctor(t) {
        return function () {
          for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
            args[_key] = arguments[_key];
          }
  
          return _construct(t, args);
        };
      };
  
      var t;
      var api = Object.create(initial);
  
      for (var n in initial.tree) {
        /* eslint guard-for-in: 0 */
        t = initial.tree[n];
  
        if (typeof t === 'function') {
          api[n.toLowerCase()] = ctor(t);
        } else {
          api[n] = Object.create(null);
  
          for (var o in t) {
            /* eslint guard-for-in: 0 */
            api[n][o.toLowerCase()] = ctor(t[o]);
          }
        }
      }
  
      return api;
    });
  
    var options;
    var logger$1;
    var fileCache = {}; // TODOS - move log somewhere. pathDiff and doing something similar in node. use pathDiff in the other browser file for the initial load
  
    var FileManager =
    /*#__PURE__*/
    function (_AbstractFileManager) {
      _inherits(FileManager, _AbstractFileManager);
  
      function FileManager() {
        _classCallCheck(this, FileManager);
  
        return _possibleConstructorReturn(this, _getPrototypeOf(FileManager).apply(this, arguments));
      }
  
      _createClass(FileManager, [{
        key: "alwaysMakePathsAbsolute",
        value: function alwaysMakePathsAbsolute() {
          return true;
        }
      }, {
        key: "join",
        value: function join(basePath, laterPath) {
          if (!basePath) {
            return laterPath;
          }
  
          return this.extractUrlParts(laterPath, basePath).path;
        }
      }, {
        key: "doXHR",
        value: function doXHR(url, type, callback, errback) {
          var xhr = new XMLHttpRequest();
          var async = options.isFileProtocol ? options.fileAsync : true;
  
          if (typeof xhr.overrideMimeType === 'function') {
            xhr.overrideMimeType('text/css');
          }
  
          logger$1.debug("XHR: Getting '".concat(url, "'"));
          xhr.open('GET', url, async);
          xhr.setRequestHeader('Accept', type || 'text/x-less, text/css; q=0.9, */*; q=0.5');
          xhr.send(null);
  
          function handleResponse(xhr, callback, errback) {
            if (xhr.status >= 200 && xhr.status < 300) {
              callback(xhr.responseText, xhr.getResponseHeader('Last-Modified'));
            } else if (typeof errback === 'function') {
              errback(xhr.status, url);
            }
          }
  
          if (options.isFileProtocol && !options.fileAsync) {
            if (xhr.status === 0 || xhr.status >= 200 && xhr.status < 300) {
              callback(xhr.responseText);
            } else {
              errback(xhr.status, url);
            }
          } else if (async) {
            xhr.onreadystatechange = function () {
              if (xhr.readyState == 4) {
                handleResponse(xhr, callback, errback);
              }
            };
          } else {
            handleResponse(xhr, callback, errback);
          }
        }
      }, {
        key: "supports",
        value: function supports() {
          return true;
        }
      }, {
        key: "clearFileCache",
        value: function clearFileCache() {
          fileCache = {};
        }
      }, {
        key: "loadFile",
        value: function loadFile(filename, currentDirectory, options, environment) {
          // TODO: Add prefix support like less-node?
          // What about multiple paths?
          if (currentDirectory && !this.isPathAbsolute(filename)) {
            filename = currentDirectory + filename;
          }
  
          filename = options.ext ? this.tryAppendExtension(filename, options.ext) : filename;
          options = options || {}; // sheet may be set to the stylesheet for the initial load or a collection of properties including
          // some context variables for imports
  
          var hrefParts = this.extractUrlParts(filename, window.location.href);
          var href = hrefParts.url;
          var self = this;
          return new Promise(function (resolve, reject) {
            if (options.useFileCache && fileCache[href]) {
              try {
                var lessText = fileCache[href];
                return resolve({
                  contents: lessText,
                  filename: href,
                  webInfo: {
                    lastModified: new Date()
                  }
                });
              } catch (e) {
                return reject({
                  filename: href,
                  message: "Error loading file ".concat(href, " error was ").concat(e.message)
                });
              }
            }
  
            self.doXHR(href, options.mime, function doXHRCallback(data, lastModified) {
              // per file cache
              fileCache[href] = data; // Use remote copy (re-parse)
  
              resolve({
                contents: data,
                filename: href,
                webInfo: {
                  lastModified: lastModified
                }
              });
            }, function doXHRError(status, url) {
              reject({
                type: 'File',
                message: "'".concat(url, "' wasn't found (").concat(status, ")"),
                href: href
              });
            });
          });
        }
      }]);
  
      return FileManager;
    }(AbstractFileManager);
  
    var FM = (function (opts, log) {
      options = opts;
      logger$1 = log;
      return FileManager;
    });
  
    /**
     * Browser Plugin Loader
     */
  
    var PluginLoader =
    /*#__PURE__*/
    function (_AbstractPluginLoader) {
      _inherits(PluginLoader, _AbstractPluginLoader);
  
      function PluginLoader(less) {
        var _this;
  
        _classCallCheck(this, PluginLoader);
  
        _this = _possibleConstructorReturn(this, _getPrototypeOf(PluginLoader).call(this));
        _this.less = less; // Should we shim this.require for browser? Probably not?
  
        return _this;
      }
  
      _createClass(PluginLoader, [{
        key: "loadPlugin",
        value: function loadPlugin(filename, basePath, context, environment, fileManager) {
          return new Promise(function (fulfill, reject) {
            fileManager.loadFile(filename, basePath, context, environment).then(fulfill).catch(reject);
          });
        }
      }]);
  
      return PluginLoader;
    }(AbstractPluginLoader);
  
    var LogListener = (function (less, options) {
      var logLevel_debug = 4;
      var logLevel_info = 3;
      var logLevel_warn = 2;
      var logLevel_error = 1; // The amount of logging in the javascript console.
      // 3 - Debug, information and errors
      // 2 - Information and errors
      // 1 - Errors
      // 0 - None
      // Defaults to 2
  
      options.logLevel = typeof options.logLevel !== 'undefined' ? options.logLevel : options.env === 'development' ? logLevel_info : logLevel_error;
  
      if (!options.loggers) {
        options.loggers = [{
          debug: function debug(msg) {
            if (options.logLevel >= logLevel_debug) {
              console.log(msg);
            }
          },
          info: function info(msg) {
            if (options.logLevel >= logLevel_info) {
              console.log(msg);
            }
          },
          warn: function warn(msg) {
            if (options.logLevel >= logLevel_warn) {
              console.warn(msg);
            }
          },
          error: function error(msg) {
            if (options.logLevel >= logLevel_error) {
              console.error(msg);
            }
          }
        }];
      }
  
      for (var i = 0; i < options.loggers.length; i++) {
        less.logger.addListener(options.loggers[i]);
      }
    });
  
    var ErrorReporting = (function (window, less, options) {
      function errorHTML(e, rootHref) {
        var id = "less-error-message:".concat(extractId(rootHref || ''));
        var template = '<li><label>{line}</label><pre class="{class}">{content}</pre></li>';
        var elem = window.document.createElement('div');
        var timer;
        var content;
        var errors = [];
        var filename = e.filename || rootHref;
        var filenameNoPath = filename.match(/([^\/]+(\?.*)?)$/)[1];
        elem.id = id;
        elem.className = 'less-error-message';
        content = "<h3>".concat(e.type || 'Syntax', "Error: ").concat(e.message || 'There is an error in your .less file') + "</h3><p>in <a href=\"".concat(filename, "\">").concat(filenameNoPath, "</a> ");
  
        var errorline = function errorline(e, i, classname) {
          if (e.extract[i] !== undefined) {
            errors.push(template.replace(/\{line\}/, (parseInt(e.line, 10) || 0) + (i - 1)).replace(/\{class\}/, classname).replace(/\{content\}/, e.extract[i]));
          }
        };
  
        if (e.line) {
          errorline(e, 0, '');
          errorline(e, 1, 'line');
          errorline(e, 2, '');
          content += "on line ".concat(e.line, ", column ").concat(e.column + 1, ":</p><ul>").concat(errors.join(''), "</ul>");
        }
  
        if (e.stack && (e.extract || options.logLevel >= 4)) {
          content += "<br/>Stack Trace</br />".concat(e.stack.split('\n').slice(1).join('<br/>'));
        }
  
        elem.innerHTML = content; // CSS for error messages
  
        browser.createCSS(window.document, ['.less-error-message ul, .less-error-message li {', 'list-style-type: none;', 'margin-right: 15px;', 'padding: 4px 0;', 'margin: 0;', '}', '.less-error-message label {', 'font-size: 12px;', 'margin-right: 15px;', 'padding: 4px 0;', 'color: #cc7777;', '}', '.less-error-message pre {', 'color: #dd6666;', 'padding: 4px 0;', 'margin: 0;', 'display: inline-block;', '}', '.less-error-message pre.line {', 'color: #ff0000;', '}', '.less-error-message h3 {', 'font-size: 20px;', 'font-weight: bold;', 'padding: 15px 0 5px 0;', 'margin: 0;', '}', '.less-error-message a {', 'color: #10a', '}', '.less-error-message .error {', 'color: red;', 'font-weight: bold;', 'padding-bottom: 2px;', 'border-bottom: 1px dashed red;', '}'].join('\n'), {
          title: 'error-message'
        });
        elem.style.cssText = ['font-family: Arial, sans-serif', 'border: 1px solid #e00', 'background-color: #eee', 'border-radius: 5px', '-webkit-border-radius: 5px', '-moz-border-radius: 5px', 'color: #e00', 'padding: 15px', 'margin-bottom: 15px'].join(';');
  
        if (options.env === 'development') {
          timer = setInterval(function () {
            var document = window.document;
            var body = document.body;
  
            if (body) {
              if (document.getElementById(id)) {
                body.replaceChild(elem, document.getElementById(id));
              } else {
                body.insertBefore(elem, body.firstChild);
              }
  
              clearInterval(timer);
            }
          }, 10);
        }
      }
  
      function removeErrorHTML(path) {
        var node = window.document.getElementById("less-error-message:".concat(extractId(path)));
  
        if (node) {
          node.parentNode.removeChild(node);
        }
      }
  
      function removeError(path) {
        if (!options.errorReporting || options.errorReporting === 'html') {
          removeErrorHTML(path);
        } else if (options.errorReporting === 'console') ; else if (typeof options.errorReporting === 'function') {
          options.errorReporting('remove', path);
        }
      }
  
      function errorConsole(e, rootHref) {
        var template = '{line} {content}';
        var filename = e.filename || rootHref;
        var errors = [];
        var content = "".concat(e.type || 'Syntax', "Error: ").concat(e.message || 'There is an error in your .less file', " in ").concat(filename);
  
        var errorline = function errorline(e, i, classname) {
          if (e.extract[i] !== undefined) {
            errors.push(template.replace(/\{line\}/, (parseInt(e.line, 10) || 0) + (i - 1)).replace(/\{class\}/, classname).replace(/\{content\}/, e.extract[i]));
          }
        };
  
        if (e.line) {
          errorline(e, 0, '');
          errorline(e, 1, 'line');
          errorline(e, 2, '');
          content += " on line ".concat(e.line, ", column ").concat(e.column + 1, ":\n").concat(errors.join('\n'));
        }
  
        if (e.stack && (e.extract || options.logLevel >= 4)) {
          content += "\nStack Trace\n".concat(e.stack);
        }
  
        less.logger.error(content);
      }
  
      function error(e, rootHref) {
        if (!options.errorReporting || options.errorReporting === 'html') {
          errorHTML(e, rootHref);
        } else if (options.errorReporting === 'console') {
          errorConsole(e, rootHref);
        } else if (typeof options.errorReporting === 'function') {
          options.errorReporting('add', e, rootHref);
        }
      }
  
      return {
        add: error,
        remove: removeError
      };
    });
  
    // Cache system is a bit outdated and could do with work
    var Cache = (function (window, options, logger) {
      var cache = null;
  
      if (options.env !== 'development') {
        try {
          cache = typeof window.localStorage === 'undefined' ? null : window.localStorage;
        } catch (_) {}
      }
  
      return {
        setCSS: function setCSS(path, lastModified, modifyVars, styles) {
          if (cache) {
            logger.info("saving ".concat(path, " to cache."));
  
            try {
              cache.setItem(path, styles);
              cache.setItem("".concat(path, ":timestamp"), lastModified);
  
              if (modifyVars) {
                cache.setItem("".concat(path, ":vars"), JSON.stringify(modifyVars));
              }
            } catch (e) {
              // TODO - could do with adding more robust error handling
              logger.error("failed to save \"".concat(path, "\" to local storage for caching."));
            }
          }
        },
        getCSS: function getCSS(path, webInfo, modifyVars) {
          var css = cache && cache.getItem(path);
          var timestamp = cache && cache.getItem("".concat(path, ":timestamp"));
          var vars = cache && cache.getItem("".concat(path, ":vars"));
          modifyVars = modifyVars || {};
          vars = vars || "{}"; // if not set, treat as the JSON representation of an empty object
  
          if (timestamp && webInfo.lastModified && new Date(webInfo.lastModified).valueOf() === new Date(timestamp).valueOf() && JSON.stringify(modifyVars) === vars) {
            // Use local copy
            return css;
          }
        }
      };
    });
  
    var ImageSize = (function () {
      function _imageSize() {
        throw {
          type: 'Runtime',
          message: 'Image size functions are not supported in browser version of less'
        };
      }
  
      var imageFunctions = {
        'image-size': function imageSize(filePathNode) {
          _imageSize();
  
          return -1;
        },
        'image-width': function imageWidth(filePathNode) {
          _imageSize();
  
          return -1;
        },
        'image-height': function imageHeight(filePathNode) {
          _imageSize();
  
          return -1;
        }
      };
      functionRegistry.addMultiple(imageFunctions);
    });
  
    //
    var root = (function (window, options) {
      var document = window.document;
      var less = lessRoot();
      less.options = options;
      var environment = less.environment;
      var FileManager = FM(options, less.logger);
      var fileManager = new FileManager();
      environment.addFileManager(fileManager);
      less.FileManager = FileManager;
      less.PluginLoader = PluginLoader;
      LogListener(less, options);
      var errors = ErrorReporting(window, less, options);
      var cache = less.cache = options.cache || Cache(window, options, less.logger);
      ImageSize(less.environment); // Setup user functions - Deprecate?
  
      if (options.functions) {
        less.functions.functionRegistry.addMultiple(options.functions);
      }
  
      var typePattern = /^text\/(x-)?less$/;
  
      function clone(obj) {
        var cloned = {};
  
        for (var prop in obj) {
          if (obj.hasOwnProperty(prop)) {
            cloned[prop] = obj[prop];
          }
        }
  
        return cloned;
      } // only really needed for phantom
  
  
      function bind(func, thisArg) {
        var curryArgs = Array.prototype.slice.call(arguments, 2);
        return function () {
          var args = curryArgs.concat(Array.prototype.slice.call(arguments, 0));
          return func.apply(thisArg, args);
        };
      }
  
      function loadStyles(modifyVars) {
        var styles = document.getElementsByTagName('style');
        var style;
  
        for (var i = 0; i < styles.length; i++) {
          style = styles[i];
  
          if (style.type.match(typePattern)) {
            var instanceOptions = clone(options);
            instanceOptions.modifyVars = modifyVars;
            var lessText = style.innerHTML || '';
            instanceOptions.filename = document.location.href.replace(/#.*$/, '');
            /* jshint loopfunc:true */
            // use closure to store current style
  
            less.render(lessText, instanceOptions, bind(function (style, e, result) {
              if (e) {
                errors.add(e, 'inline');
              } else {
                style.type = 'text/css';
  
                if (style.styleSheet) {
                  style.styleSheet.cssText = result.css;
                } else {
                  style.innerHTML = result.css;
                }
              }
            }, null, style));
          }
        }
      }
  
      function loadStyleSheet(sheet, callback, reload, remaining, modifyVars) {
        var instanceOptions = clone(options);
        addDataAttr(instanceOptions, sheet);
        instanceOptions.mime = sheet.type;
  
        if (modifyVars) {
          instanceOptions.modifyVars = modifyVars;
        }
  
        function loadInitialFileCallback(loadedFile) {
          var data = loadedFile.contents;
          var path = loadedFile.filename;
          var webInfo = loadedFile.webInfo;
          var newFileInfo = {
            currentDirectory: fileManager.getPath(path),
            filename: path,
            rootFilename: path,
            rewriteUrls: instanceOptions.rewriteUrls
          };
          newFileInfo.entryPath = newFileInfo.currentDirectory;
          newFileInfo.rootpath = instanceOptions.rootpath || newFileInfo.currentDirectory;
  
          if (webInfo) {
            webInfo.remaining = remaining;
            var css = cache.getCSS(path, webInfo, instanceOptions.modifyVars);
  
            if (!reload && css) {
              webInfo.local = true;
              callback(null, css, data, sheet, webInfo, path);
              return;
            }
          } // TODO add tests around how this behaves when reloading
  
  
          errors.remove(path);
          instanceOptions.rootFileInfo = newFileInfo;
          less.render(data, instanceOptions, function (e, result) {
            if (e) {
              e.href = path;
              callback(e);
            } else {
              cache.setCSS(sheet.href, webInfo.lastModified, instanceOptions.modifyVars, result.css);
              callback(null, result.css, data, sheet, webInfo, path);
            }
          });
        }
  
        fileManager.loadFile(sheet.href, null, instanceOptions, environment).then(function (loadedFile) {
          loadInitialFileCallback(loadedFile);
        }).catch(function (err) {
          console.log(err);
          callback(err);
        });
      }
  
      function loadStyleSheets(callback, reload, modifyVars) {
        for (var i = 0; i < less.sheets.length; i++) {
          loadStyleSheet(less.sheets[i], callback, reload, less.sheets.length - (i + 1), modifyVars);
        }
      }
  
      function initRunningMode() {
        if (less.env === 'development') {
          less.watchTimer = setInterval(function () {
            if (less.watchMode) {
              fileManager.clearFileCache();
              loadStyleSheets(function (e, css, _, sheet, webInfo) {
                if (e) {
                  errors.add(e, e.href || sheet.href);
                } else if (css) {
                  browser.createCSS(window.document, css, sheet);
                }
              });
            }
          }, options.poll);
        }
      } //
      // Watch mode
      //
  
  
      less.watch = function () {
        if (!less.watchMode) {
          less.env = 'development';
          initRunningMode();
        }
  
        this.watchMode = true;
        return true;
      };
  
      less.unwatch = function () {
        clearInterval(less.watchTimer);
        this.watchMode = false;
        return false;
      }; //
      // Synchronously get all <link> tags with the 'rel' attribute set to
      // "stylesheet/less".
      //
  
  
      less.registerStylesheetsImmediately = function () {
        var links = document.getElementsByTagName('link');
        less.sheets = [];
  
        for (var i = 0; i < links.length; i++) {
          if (links[i].rel === 'stylesheet/less' || links[i].rel.match(/stylesheet/) && links[i].type.match(typePattern)) {
            less.sheets.push(links[i]);
          }
        }
      }; //
      // Asynchronously get all <link> tags with the 'rel' attribute set to
      // "stylesheet/less", returning a Promise.
      //
  
  
      less.registerStylesheets = function () {
        return new Promise(function (resolve, reject) {
          less.registerStylesheetsImmediately();
          resolve();
        });
      }; //
      // With this function, it's possible to alter variables and re-render
      // CSS without reloading less-files
      //
  
  
      less.modifyVars = function (record) {
        return less.refresh(true, record, false);
      };
  
      less.refresh = function (reload, modifyVars, clearFileCache) {
        if ((reload || clearFileCache) && clearFileCache !== false) {
          fileManager.clearFileCache();
        }
  
        return new Promise(function (resolve, reject) {
          var startTime;
          var endTime;
          var totalMilliseconds;
          var remainingSheets;
          startTime = endTime = new Date(); // Set counter for remaining unprocessed sheets
  
          remainingSheets = less.sheets.length;
  
          if (remainingSheets === 0) {
            endTime = new Date();
            totalMilliseconds = endTime - startTime;
            less.logger.info('Less has finished and no sheets were loaded.');
            resolve({
              startTime: startTime,
              endTime: endTime,
              totalMilliseconds: totalMilliseconds,
              sheets: less.sheets.length
            });
          } else {
            // Relies on less.sheets array, callback seems to be guaranteed to be called for every element of the array
            loadStyleSheets(function (e, css, _, sheet, webInfo) {
              if (e) {
                errors.add(e, e.href || sheet.href);
                reject(e);
                return;
              }
  
              if (webInfo.local) {
                less.logger.info("Loading ".concat(sheet.href, " from cache."));
              } else {
                less.logger.info("Rendered ".concat(sheet.href, " successfully."));
              }
  
              browser.createCSS(window.document, css, sheet);
              less.logger.info("CSS for ".concat(sheet.href, " generated in ").concat(new Date() - endTime, "ms")); // Count completed sheet
  
              remainingSheets--; // Check if the last remaining sheet was processed and then call the promise
  
              if (remainingSheets === 0) {
                totalMilliseconds = new Date() - startTime;
                less.logger.info("Less has finished. CSS generated in ".concat(totalMilliseconds, "ms"));
                resolve({
                  startTime: startTime,
                  endTime: endTime,
                  totalMilliseconds: totalMilliseconds,
                  sheets: less.sheets.length
                });
              }
  
              endTime = new Date();
            }, reload, modifyVars);
          }
  
          loadStyles(modifyVars);
        });
      };
  
      less.refreshStyles = loadStyles;
      return less;
    });
  
    /**
     * Kicks off less and compiles any stylesheets
     * used in the browser distributed version of less
     * to kick-start less using the browser api
     */
    var options$1 = defaultOptions();
  
    if (window.less) {
      for (var key in window.less) {
        if (window.less.hasOwnProperty(key)) {
          options$1[key] = window.less[key];
        }
      }
    }
  
    addDefaultOptions(window, options$1);
    options$1.plugins = options$1.plugins || [];
  
    if (window.LESS_PLUGINS) {
      options$1.plugins = options$1.plugins.concat(window.LESS_PLUGINS);
    }
  
    var less = root(window, options$1);
    window.less = less;
    var css;
    var head;
    var style; // Always restore page visibility
  
    function resolveOrReject(data) {
      if (data.filename) {
        console.warn(data);
      }
  
      if (!options$1.async) {
        head.removeChild(style);
      }
    }
  
    if (options$1.onReady) {
      if (/!watch/.test(window.location.hash)) {
        less.watch();
      } // Simulate synchronous stylesheet loading by hiding page rendering
  
  
      if (!options$1.async) {
        css = 'body { display: none !important }';
        head = document.head || document.getElementsByTagName('head')[0];
        style = document.createElement('style');
        style.type = 'text/css';
  
        if (style.styleSheet) {
          style.styleSheet.cssText = css;
        } else {
          style.appendChild(document.createTextNode(css));
        }
  
        head.appendChild(style);
      }
  
      less.registerStylesheetsImmediately();
      less.pageLoadFinished = less.refresh(less.env === 'development').then(resolveOrReject, resolveOrReject);
    }
  
    return less;
  
  }));